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Narrow / 3-across booster car seats

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Booster seats that carry the narrow / 3-across spec — 6 models to shortlist from.

Short answer: Going by each maker's manual, high-back booster mode goes up to 120 lb on the 2 seats that have it, and backless booster mode up to 120 lb. Useful life is 7 to 10 years where the manual gives one.

Fit is decided by your seat manual + your vehicle manual. This page lists published specs to help you shortlist — it is not installation or safety advice, and it does not confirm a seat fits a specific car. Confirm install with the manuals, NHTSA, or a free certified car-seat technician (CPST) check.

Last verified 2026-06-11 · 6 models

Car seatStageNarrow (3-across)Ext. rear-facingFAALightweightBuy
Clek OobrBooster40–100 lbBooster✓–––See price
on Amazon
mifold Grab-and-GoBooster40–100 lbBooster✓––✓See price
on Amazon
Graco RightGuide PortableBooster50–120 lbBooster✓––✓See price
on Amazon
Diono Monterey 4DXTBooster40–120 lbBooster✓–––See price
on Amazon
Clek OzziBooster40–120 lbNHTSA notice 2022Booster✓––✓See price
on Amazon
Diono Solana 2Booster40–120 lbBooster✓––✓See price
on Amazon

These are the slim models families use for 3-across — but three fit only if their combined width fits your vehicle's bench, so test-fit in YOUR car.

Weight limits and useful life, seat by seat

The weight ranges each maker prints in the seat's manual. Tap a seat to see it side by side with a similar model, with height limits and a link to its manual.

Car seatHigh-back boosterBackless boosterUseful life
Clek Oobr40–100 lb40–100 lb9 yrs
mifold Grab-and-Go—40–100 lb7 yrs
Graco RightGuide Portable—50–120 lb10 yrs
Diono Monterey 4DXT40–120 lb40–120 lb8 yrs from purchase
Clek Ozzi—40–120 lb9 yrs
Diono Solana 2—40–120 lb8 yrs from purchase

“—” means the manual we cite gives no figure for that mode. Useful life counts from the date of manufacture unless it says “from purchase”. How these are sourced

Common questions

Up to what weight can these be used as a booster?

In high-back booster mode the maximum is between 100 and 120 lb; the Diono Monterey 4DXT goes to 120 lb. As a backless booster the maximum is between 100 and 120 lb. A booster also needs the seat belt to fit your child, so check the height range in the manual too.

How long do narrow booster car seats last before they expire?

The manuals list a useful life of 7 to 10 years. Most count from the date of manufacture; the Diono Monterey 4DXT and the Diono Solana 2 count from the date of purchase. More by brand on car seat expiration.

More: all booster seats · all narrow / 3-across seats · how to check fit →