10 Best Narrow Car Seats for Three Across (October 2026)

If you are shopping for the best narrow car seats for three across, one number decides almost everything: the width of the seat at its base, measured in inches, before any cup holder or armrest is added. Two seats under 17 inches wide can share a bench with a booster. Three seats at 19 inches each will not fit in anything short of a very large SUV.

The direct answer, since it comes up constantly: the thinnest option in this roundup is the Chicco GoFit ClearTex Plus backless booster at about 14.5 inches wide. Among seats with a harness, the Diono Everett NXT booster runs roughly 16.5 inches and the Graco SlimFit3 LX convertible sits at 16.7 inches. A low backless booster tucked next to two taller seats is the trick that makes most three-across layouts work.

I assembled this list by weighing four things in order: published width, whether the seat installs with a seat belt in a tight row, how low the shell sits so it can tuck under the curve of a taller neighbor, and how long the seat lasts before your family is solving the geometry puzzle again. I also read the review patterns closely, because a narrow seat that frustrates people during installation fails at the only job it has.

One more thing that changes the math for everyone: in most vehicles the lower anchors in the center seating position are unusable, so all three seats in a three-across setup get installed with the seat belt. A built-in lockoff or belt tensioning device is worth more than a small width advantage. If your youngest is still in a carrier, our guide to the best infant car seats is the natural starting point before you move to the convertible stage.

Everything below is written for 2026 families who have actually tried to install three seats and then measured twice. Read the measuring section before you buy anything, because a 3-inch miss on your bench can cost you a full set of returns.

Our Top 3 Picks for Fitting Three Seats Across

The SlimFit3 LX wins because it solves the mixed-stage problem in one shell, not because it is the narrowest thing here. The Radian 3R is the endurance pick, and the Chicco GoFit is the width champion that makes the other two easier to place.

Comparing All 10 Narrow Car Seats Side by Side

Two entries deserve a note before the detailed reviews. The Safety 1st Grow and Go is listed at 19 inches, which is the full ComfortWings extension rather than the base width, so it is wider than it looks in a showroom. The Baby Trend Trooper Slim and the Baby Trend Hybrid SI do not publish an exact width, which is itself a useful signal.

1. Graco SlimFit3 LX – the 16.7-Inch Workhorse for Mixed-Age Rows

The SlimFit3 LX is the seat I would build a three-across row around first. At 16.7 inches wide with a low-profile shell, it is the rare convertible that is engineered for the three-across problem rather than trimmed down to fit it, and owners with packed back seats consistently report that it fits where nothing else would.

An owner in the Tesla Model Y community documented three SlimFit3 LX units installed across the rear bench, and the author of a widely read twins blog runs the same seat three-across in a Mazda CX-7 and in the second row of a Honda Pilot. Those are ordinary vehicles, not exceptions.

The single most important detail for a three-across family is the No-Rethread Simply Safe harness. The headrest and harness move together in one motion, so getting a growing child positioned correctly does not mean rethreading straps in a parking lot between two other seats.

Rear-Facing From 5 to 40 Pounds Keeps the Middle Position Free

Staying rear-facing as long as the child fits is the single most protective choice you can make, and this seat allows that up to 40 pounds without changing hardware. For a family running infant, convertible and booster stages at once, having the smallest child in a rear-facing convertible instead of an infant carrier keeps the install simple.

Once the child is ready, the same shell moves to forward-facing harness mode from 26.5 to 65 pounds, then to highback booster mode from 40 to 100 pounds. That is a 10-year-type arc from a single seat, which is exactly what keeps a three-across row stable instead of forcing a re-solve every time someone hits a growth marker.

Side-Impact Engineering at a Narrow Width

Graco describes the shell as ProtectPlus engineered to its newest testing standards. In a row of three, the outer seats do the heavy work for side impacts, since the middle position is shielded by the seats on either side. The SlimFit3 LX is one of the few 16.7-inch seats with meaningful side-energy management built into that narrow shell.

Worth noting: the federal side-impact standard tightened under FMVSS 213a, which took effect June 30, 2025. Slim seats are the ones most likely to have needed a headrest redesign or added external side pods to meet it, so buying a current-production seat rather than an older design is more important than usual in this category.

Where It Falls Short

The rear-facing recline takes practice, especially for a newborn, and it is the adjustment most often rushed in a tight row. Side openings in the shell let cabin air blow directly at the child’s legs, and several reviewers note the seat can run warm in hot weather with three bodies sharing the same enclosed bench.

It is also not the plushest convertible in the roundup. If your child is sensitive to padding, test the insert before committing, because a narrow shell and a thick cushion compete for the same inches.

2. Diono Radian 3R – Steel Frame, Four Modes, Ten Years

The Radian 3R is the longest-serving answer to the three-across question, and the review base reflects that. It covers 5 to 120 pounds across four modes, which means a family that buys it for a newborn is not shopping again until the child is out of booster mode entirely.

One parent reports running three Radian-family seats across a Toyota Prius with enough room to still climb into the back, and other owners fit them in a Scion xB and a Volvo XC70. That range of vehicles is the point: this is a seat that works in a bench nobody expected to hold three.

The Steel Core Is the Reason for the Weight

The shell is built around an automotive-grade high-strength steel frame, and that is why the seat is heavy. Owners describe it as a labor-intensive install and recommend a certified child passenger safety technician, which is good advice for a seat with this many modes. In exchange you get a structure that feels very solid in a crash and does not flex when you cinch it down.

ComfortPlus memory foam is included, the covers come off and are machine washable, and the SuperLatch open-loop belt path connectors keep the routing readable. Those are the features that matter in a row of three, where a confusing belt path costs you half an hour every time.

Four Modes and Folding for Travel

Rear-facing, forward-facing harness, highback booster and backless booster cover the full arc, with rear-facing capability to 50 pounds. The seat also folds flat for storage and is airline approved, which is genuinely useful for a grandparent vehicle or a family that travels with a full set.

Plan the mode changes. A seat that converts between four configurations is only convenient if you change modes before you need to, not at the shoulder of a highway when the child is at the top of the harness range.

Where It Falls Short

Weight is the honest drawback, and it is a big one for a family moving seats between a commuter car and a family SUV. The install is more complex than the 16.7-inch convertibles in this roundup, and the steep rear-facing recline can require moving the front seat forward, which then eats leg room for the person in front.

It is also not easily installed rear-facing in a center position with a fixed headrest. Since the center seat is the hardest position in any three-across row, test that one first before committing to three of these.

3. Chicco GoFit ClearTex Plus – the Slimest Footprint at About 14.5 Inches

This is the narrowest seat here by a clear margin, at roughly 14.5 inches in its backless profile. That width is the entire reason to consider it: at 16.5 inches for a harness seat, roughly two extra inches of margin is often the difference between three seats fitting and two fitting with a frustrated adult in the back.

It also anchors, which is unusual for a backless booster in this category. The LATCH attachment with one-hand quick release means the seat stays with the vehicle instead of becoming a loose object in the cargo area, and many families keep one in each of their cars because it is light enough to carry.

Integrated Belt Guides Do the Positioning Work

Integrated lap belt guides and a shoulder belt clip are built into the seat, so the adult does not have to work out routing with a moving child in the back. On a narrow booster the belt path is fiddly, and the guides remove most of that friction. Reviewers also call out the contoured ErgoBoost seat with double foam padding as comfortable for larger children rather than a placeholder.

Two fold-away dishwasher-safe cup holders and a machine-washable seat pad cover the daily-use details. The armrest covers pop out for cleaning, which matters more than it sounds in a seat that lives in three vehicles.

Greenguard Gold and Flame-Retardant-Free Fabric

This is the one pick in the roundup that is both Greenguard Gold certified and built without flame retardants in the ClearTex construction. For parents who have been reading about fabric chemicals, that is a real differentiator, and it is the sort of specification that disappears from most shopping pages.

There is a built-in carry handle for travel, which pairs well with the low weight. If you shuttle a booster to a grandparent house or a road trip vehicle, that handle is not a small detail.

Where It Falls Short

It is a backless booster, so there is no head or back support. It is rated for children 40 to 110 pounds and 44 to 57 inches tall with a minimum age of four, which means it is a fourth-and-upper stage and not a solution for a toddler.

The written instructions take a moment to get the hang of, and the foam insert must be hand rinsed rather than machine washed. Reviewers are otherwise consistent in their praise, which is why the rating sits where it does.

4. Diono Connect3 R – Built Around the Buckle, Not Just the Width

Most three-across failures happen at the buckle, not at the armrest. Three seats can technically line up and still fail because a 4-year-old cannot reach the buckle stalk with a hand while wearing a winter coat. The Connect3 R is the only pick here designed from that problem outward, and it is under 17 inches wide.

The patented EasyPath contour carves out the space where the buckle sits, and the cup holder is removable and nests between two Connect3 seats. Owners in compact sedans and older SUVs report that it fits tightly sculpted benches in modern cars without modification.

A 40 to 120 Pound Range With an 11-Position Headrest

The combined DualProtect head and backrest adjusts through 11 positions, which is the widest range in this group and the difference between a booster that fits your tall child and one that does not. It converts to a backless booster with a shoulder belt positioning clip and a carry handle once the harness stages are done.

The SleepyCheek ergonomic headrest is angled for naps with head and neck support, and a two-position reclining backrest sits on a 2TexFoam base. Ventilation channels run along the head and backrest, which matters when the seat is pressed between two other seats with no airflow.

Three Realistic Weak Spots

The rating trails the higher-volume seats in this roundup, and the reasons are consistent rather than dramatic. Some copies arrive without the cup holder even though it is pictured on the box, so check the box before you leave the house. The belt path is not obvious and needs reinforcing with kids, since it has to run in front of the armrests.

The top and bottom sections separate easily, so it needs a bag if you fly with it, and some reviewers find it heavier than a basic booster. None of that touches safety; it is a convenience-versus-weight trade.

5. Graco Tranzitions – Harness Then Booster in a 17-Inch Shell

The Tranzitions answers a specific question: what does the middle seat look like when the child there is still in a harness but the family wants one seat to do everything later. It covers forward-facing harness from 26.5 to 65 pounds, then highback and backless booster from 40 to 100 pounds.

The No-Rethread Simply Safe system means the headrest and harness move together, and the nine-position one-hand headrest adjustment is quick as the child grows. That matters more in a packed row than it would in an open bench.

Where the 17-Inch Shell Costs You

At 17 inches in the shell, this is wider than the purpose-built three-across seats in this roundup, and that is the whole trade. A family running a newborn, a toddler in a harness and a booster has a tight sum to work with, and two inches on one seat can consume the gap that makes the buckle reachable.

In a mid-size sedan or a crossover, 17 inches is usually manageable. In a compact car with sculpted seats, it is the seat most likely to be the reason the row does not fit. Measure before you choose it over a 16.5-inch or 16.7-inch option.

Lightness Is the Reason It Earns Its Place

The lightweight, portable shell is designed for moving between vehicles, and for a family with a second car or a grandparent pickup schedule that is a genuine advantage. In backless mode all back and head support is removed, so the seat is only as good as the vehicle seat back under your child.

Reviewers report satisfaction clustered around the no-rethread harness and the ease of moving the seat between cars, with roughly 86 percent five-star feedback. The seat is a good middle ground: not the narrowest option, but a wide range of stages in one lightweight shell.

6. Diono Everett NXT – Rigid LATCH in a 16.5-Inch Booster

The Everett NXT is the narrow booster here that still anchors, and the rigid LATCH connectors are the reason. Rigid arms plug straight into the anchor points without a tightening strap, which means no slack to pull out and no extra step when you are installing three seats one after another in a parking lot.

Reviewers with three-across layouts, including a Volvo XC90 family, confirm the fit, and people with limited dexterity and grandparents are singled out as especially happy with how simply the connectors attach.

Two Layers of Side Impact at 16.5 Inches

The seat carries two layers of side impact protection across a 40 to 120 pound range, with a seven-position adjustable headrest. A booster in the outer position of a three-across row is the seat most exposed to side impact, so side-energy management matters more here than in the middle.

Open loop belt guides give children a path to self-buckle without the belt snagging, and the deep padded backrest has removable machine-washable covers. The rigid LATCH arms also flip inward in vehicles without anchors, so the seat can still live in an older car.

Two Design Details Worth Knowing

The headrest wings can dig into the shoulders of taller children when set in the manual position, so raise it as your child grows rather than leaving it low. Cup holders are sold separately and press onto a small plastic stem that some reviewers doubt will last, which is worth considering before you plan on a cup in this position.

The back panel can pop off during moves and be difficult to refit. That is a nuisance rather than a safety issue, but in a three-across household where seats move constantly, it is the kind of thing that shows up on a bad morning.

7. Baby Trend Trooper Slim – a Lightweight Convertible With Mixed Reviews

The Trooper Slim is a 3-in-1 convertible built around a slim profile for multi-seat installations, and families who have installed it in cramped vans and small sedans like exactly that. It moves through rear-facing, forward-facing and booster modes with an adjustable headrest and harness.

It is also the most polarizing seat in this roundup, and we would rather tell you that than round it off. The rating sits at 4.0 with a meaningful cluster of one-star feedback, so buy it knowing you may need to troubleshoot the harness after a week.

The Adjustable Angle Is the Standout Feature

Families that like the seat consistently point to the highly adjustable angle and the headrest support when a toddler falls asleep. That is a real advantage in a three-across row where you cannot tilt the whole bench and no one has room to work around the seat.

It is a lightweight build, which makes it the easiest convertible in this roundup to move between a second vehicle and a carpool. If you expect to reinstall the seat more than a few times a year, that is worth real weight in the decision.

Read the Complaints Before Ordering

Owners report harness straps that are not even and can be hard to tighten properly, tucked buckle stalks that twist repeatedly and become hard to reach, and material that feels thin and snags after about a week of use. The seat can also feel insecure rear-facing unless it is wedged firmly against the front seat.

In a three-across row, a twisted buckle stalk is a bigger problem than it is in an open bench, because the child has less room to reach. If you cannot test it in person, a visit to a certified child passenger safety technician after delivery is worth scheduling.

8. Graco TurboBooster 2.0 – Recline and Retractable Cup Holders

The TurboBooster 2.0 is the one to look at when your oldest child falls asleep in the back. Parents repeatedly mention that the recline is enough for a sleeping child to keep their head supported on long drives, which is not something most boosters at this level manage.

It converts from highback to backless, carries children from 40 to 100 pounds, and uses open-loop belt guides with independent self-buckling. The hide-away retractable cup holders are deep enough for a water bottle, which matters when there is no door pocket within reach.

ProtectPlus Engineering With EPS Foam

Graco describes the seat as ProtectPlus engineered with frontal, rear and rollover crash testing, and it uses EPS energy-absorbing foam for impact management. Height-adjustable armrests and headrests let the seat grow with the child, and the assembly is low-effort out of the box.

At a 17.5 inch footprint it is one of the wider boosters here, so plan the row accordingly. It pairs well with two narrower convertibles where the booster sits at the end of the bench, where its slightly larger footprint has the least effect on the buckle.

The Missing Anchor Is the Real Limitation

It does not anchor to the vehicle with LATCH, and an unoccupied seat can shift during travel. In a three-across row, that is a consideration rather than a dealbreaker, because a booster is a belt-positioning device and a child wearing the belt is the restraint that matters.

Younger children generally need help buckling because the armrests sit over the buckle stalk, and some reviewers describe the padding as thin. Both are complaints about daily convenience, not protection.

9. Safety 1st Grow and Go – Folds Flat, Expands to 19 Inches

The Grow and Go is the pick for a family that moves seats constantly, because it folds into two pieces and stores compactly. Owners highlight the low weight as the deciding factor, especially coming from heavier boosters they were carrying between cars daily.

It is a 2-in-1 belt-positioning booster that converts from highback to backless, rated for 40 to 100 pounds and 43.4 to 57 inches, with a ten-position headrest that many owners say grows with the child and still has room to spare.

ComfortWings Expand, and So Does the Width

The ComfortWings backrest wings expand as the headrest rises, which is a neat way to keep a booster narrow for smaller children and add support as the child grows. It is also the reason the published width is 19 inches at full extension, the widest in this roundup, so the low setting is what you should be measuring against your bench.

Shoulder and lap belt guides position the belt correctly, the seat pad is removable and machine washable, and the two cup holders are removable and dishwasher safe. Several reviewers note children can buckle themselves using the guides, and kids report it stays comfortable on longer rides.

Plan for the Width at Full Extension

If you fit this seat across your back bench, measure at the headrest height your child will actually use rather than the collapsed width. Two seats at 19 inches plus a 16.7-inch convertible is a sum that rules out most sedans, so this one belongs at the end of a bench in a crossover or SUV, not in the middle.

It also does not latch to the vehicle seat, so an unoccupied Grow and Go can become a projectile during travel, which is the single most common reservation in the reviews. Backless mode is expected to be less comfortable on long rides.

10. Baby Trend Hybrid SI – Side-Impact Focus, Complicated Instructions

The Hybrid SI is a 3-in-1 combination booster with a side-impact focused design, dual cup holders and a cushioned interior that parents say their children actually nap in. For a family that wants a side-impact emphasis without moving to a seat built for a different stage, it is worth a look.

It is also the most instruction-heavy seat in this roundup. The rating reflects that: parents like the comfort and the 3-in-1 layout, but the manual and the changing harness routing push the score down.

The Harness Routing Changes at 40 Pounds

This is the detail that catches families out. The 5-point harness runs small with little adjustment travel, and the belt routing changes as the child crosses 40 pounds, so the setup that worked last month is not the setup that works now. Read that section of the manual before your child gets there rather than at the shoulder of a highway.

Several reviews also describe a back panel that detaches easily and is hard to refit, and a seat that does not sit or install cleanly in every vehicle, with a Jeep Wrangler named specifically. Check your own vehicle rather than assuming.

Where It Fits in a Three-Across Row

The slim design helps in a crowded row, and the adjustable headrest plus the 3-in-1 growth stages extend the usable life enough to be worth considering. Owners also mention wanting more padding for longer trips, which is a fair note for a seat that people otherwise describe as comfortable.

Set expectations on the manual. If you are comfortable reading a routing diagram before you buy, this is a cushioned, side-impact-focused combination booster that will grow with your child. If you are not, pick a seat with a simpler single-path install.

How to Measure Your Back Seat Before You Buy

Most people measure the wrong number. The width of the bench at the top, shoulder to shoulder across the upholstery, tells you almost nothing, because the seat belt anchors, the buckle stalks and the vehicle head restraints all intrude at seat-belt height.

Measure at the Seat Bight, Not Across the Cushion

Measure the flat usable width at the seat bight, from the door trim on one side to the seat belt anchor post on the far side. That is the plane your car seats actually occupy. Then measure each seat at its own base rather than trusting a listing photo.

Add the three base widths together, then subtract about an inch so the buckle stalks stay reachable. If the sum is under your measured usable width, you have a workable row. If it is over by more than a few inches, no amount of clever technique will close the gap.

Account for the Shape, Not Just the Width

Car seats are curved, not rectangular. A low backless booster tucks into the curve of a taller convertible beside it, which is why a 14.5-inch booster and two 16.7-inch convertibles can work where three 17.5-inch boosters cannot. The lowest seat in the row should always be the one with the least height, not the one with the smallest number.

There are also wasted inches between the door and the seat belt anchor that a well-shaped seat can occupy. And remember that a vehicle head restraint that protrudes low can force a forward-facing seat forward, changing the geometry of the entire row.

Verify the Center Position Separately

Most vehicles do not have usable lower anchors in the center seating position. That means the middle seat is almost certainly a seat belt install, and if it is a rear-facing convertible, a fixed headrest in the center can make the install impossible. Check the center position on its own before you assume a three-across row works.

Buying Guide: What Matters More Than Width in a Three-Across Setup

Built-In Seat Belt Lockoffs Are the Feature That Matters Most

In a three-across row, all three seats usually go in with the seat belt, and a built-in lockoff or belt tensioning device lets you lock the belt without a separate locking clip. Without one, you are threading a clip through the belt webbing at the shoulder or behind the seat back while an adult holds two other children still. Certified child passenger safety technicians consistently recommend seats with integrated lockoffs for exactly this reason.

Rigid LATCH arms are the same idea for the outer positions: they click straight in with no strap to tighten and no slack to remove. The Diono Everett NXT is the clearest example in this roundup.

What FMVSS 213a Means for Narrow Seats

The federal side-impact standard tightened under FMVSS 213a, which took effect June 30, 2025. The practical consequence for narrow seats is that the headrest and side structure had to do more work, which has led to deeper wings, redesigned headrests and external side-impact pods on some models. Slim seats are the most likely to be affected, because shaving the shell was the easiest place to find the inches.

The reassurance that matters: a narrow seat has to pass the same federal crash standards as a wide one, and the ones in this roundup carry current side-impact engineering such as Graco ProtectPlus and two layers of side protection on the Everett NXT. Buy a current-production seat, and confirm the model number is not a discontinued design sold by a third party.

Age-Keyed Three-Across Build Lists

Matching seats to your actual children is easier than most shopping journeys make it. Start from the oldest child, since they need the most width, and work inward.

Newborn, 3-year-old, 5-year-old: a rear-facing convertible for the newborn, a forward-facing harness or harness booster in the middle, and a slim backless or highback booster on the outboard side. The backless booster should go on the outboard side because it is the narrowest and the least tall.

Two infants plus a booster: two identical seats make a symmetric row far easier to fit, and the booster tucks into the space beside them. Buying a matching pair of infant or convertible seats is worth more here than buying the two individually narrowest models.

Two convertibles plus a backless booster: this is the most comfortable three-across configuration because the booster contributes almost no height. Two 16.5 to 16.7-inch convertibles plus a 14.5-inch backless booster is a sum most mid-size sedans can handle.

Three boosters: keep two of them backless once children are ready, since backless boosters have no headrest shell to add width. This is the configuration where a 17.5 or 19 inch booster works fine, because nothing else in the row is tall.

Sedan, Small Crossover or Three-Row: What Actually Fits

In a mid-size sedan, treat the sum of the three base widths as nearly fixed. Convertibles dominate what fits, and the middle position must be checked for lower anchor and headrest compatibility. Compact sedans and two-door coupes are the hardest cases, and a 14.5-inch backless booster at the end is often the difference.

In a small crossover, you gain a few inches of bench length and usually flatter seats, which helps the recline stay true. The Tesla Model Y community documents three Graco SlimFit3 LX units across a rear bench narrower than the car suggests, while Rivian R2 owners report fitting three car seats across in a cabin wider than a Model 3 or Model Y with more legroom behind them.

In a three-row SUV, the decision is often whether the second row can hold three and you keep the third for cargo, or whether you fit two in the second row and one in the third. Owners of larger vehicles describe workable configurations using two narrow seats in a second row with a third-row position folded flat for cargo, which is usually the compromise that keeps the daily row readable.

Narrow Seats We Would Skip, and the SlimFit Naming Trap

Several widely recommended models do not belong in a three-across row, and parents on every parenting forum ask about them repeatedly. The regular Graco SlimFit, the Chicco KeyFit30, the Peg Perego 4-35, the Baby Trend Flex-Loc, the Uppababy Mesa and the Cybex Aton2 are all wide relative to the purpose-built slim seats here. The Cosco Scenera NEXT is a common budget recommendation that does not carry the 3-across geometry.

Two naming traps cause more wasted money than anything else in this category. First, the Graco SlimFit3 LX and the Graco SlimFit 3-in-1 are different seats with nearly identical names, and the tell is the release lever and base: the slim model has the narrow base and the gray lever, the standard model has the wider base and the red lever. Check the model number, not the product name.

Second, the Maxi-Cosi RodiFix is discontinued and the RodiSport is not a like-for-like replacement, and the IMMI Go is no longer available in the US. Buying either by name is a common way to end up with a seat that does not fit what you assumed. Cross-check the model number against your vehicle’s manual before you order three of anything.

Two Steps That Prevent Most Problems

First, read your vehicle manual section on child restraints before you buy, not after. It tells you where the anchors are, which positions support a forward-facing seat, and whether your head restraints need to be removed or adjusted, and that information should shape the model list.

Second, book a certified child passenger safety technician visit once the seats are installed. In a three-across row, even one tight install left unchecked can compromise a row that was engineered carefully. Technicians on certification forums are the people who spot a belt path that is technically correct and practically loose.

Frequently Asked Questions

Conclusion: Which Narrow Car Seats Fit Three Across

Start with the seat your oldest child needs, then fill inward. If you want one seat that handles every stage in the middle position, the Graco SlimFit3 LX at 16.7 inches is the one to build around. If you want a single seat that lasts from birth to booster for ten years and you can handle the weight, the Diono Radian 3R covers 5 to 120 pounds across four modes.

If width is the binding constraint, the Chicco GoFit ClearTex Plus at about 14.5 inches buys you the most room, and the Diono Connect3 R is the pick when the buckle has to stay reachable for small hands. Diono Everett NXT is worth a close look when you want a booster that still anchors with rigid LATCH, and the Graco Tranzitions is a good middle-seat harness-to-booster bridge if 17 inches fits your bench.

Measure first, buy second, and check the model number rather than the product name. That single habit, avoiding the SlimFit naming trap and the discontinued RodiFix listings, prevents most of the returns we hear about, and it makes the best narrow car seats for three across a decision you will only make once.