The One4Life® Slim all-in-one car seat takes your child from birth to big kid with trusted Britax safety, ClickTight® installation, and a slim SpaceSaver™ design. As a convertible and harness-2-booster seat in one, it grows with your child for 10 years.

It starts rear-facing with an extended capacity of up to 22.7 kg (50 lbs.), so your child can ride rear-facing longer. It easily converts to forward-facing toddler mode (up to 29.5 kg/65 lbs.) and high-back belt-positioning booster mode (up to 54.4 kg/120 lbs.) when your child is ready. With a slim outside and spacious inside, the 44.5 cm (17.5”) seat is designed to fit 3 across* without compromising safety and comfort. ClickTight helps you install with confidence, every time. 

One4Life Slim features an anti-rebound bar, a high-strength steel frame, a SafeCell® crumple zone, and a V-shaped tether. As your child grows, you can easily adjust the 15-position no-rethread harness and headrest with one hand. With cooling channels, premium padding, a lower infant insert and upper body support pillow, and built-in armrests, your child will love every ride. *Britax cannot guarantee 3-across fitment in all vehicles.

All-in-One Car Seat: One4Life® Slim is a convertible and harness-2-booster seat in one! It easily converts from a rear-facing infant and toddler seat (2.3-22.7 kg/5-50 lbs.) to a forward-facing seat (10-29.5 kg/22-65 lbs.) to a high-back booster seat (18.1-54.4 kg/40-120 lbs.)

ClickTight® Installation: Install with confidence in 3 easy steps: pinch to open, thread and buckle, click it closed!

SpaceSaver™ Design: Slim outside, spacious inside! The 44.5 cm (17.5”) seat is designed to fit 3 across without compromising on trusted Britax safety and premium comfort *Britax cannot guarantee 3-across installation fitment in all vehicles

Premium Car Seat Cover: Features a soft knit fabric with woven mélange accents that are made from recycled polyester; the cover is safe to machine-wash and dry and naturally flame retardant with no added FR chemicals

Trusted Britax Safety: This slim car seat features an anti-rebound bar, a patented V-shaped tether, SafeCell® technology, a high-strength steel frame, and two layers of energy management

Hassle-Free Cleanup: Extra space between the shell and base means you can clean under the seat with ease – and with minimal grooves in the seating area and base, you can wipe it down with no fuss

Comfortable Rides: This slim car seat includes comfort pads, built-in cooling channels, a lower infant insert and upper body support pillow, plush padding, and a tag-free headrest

Easy to Adjust: The 15-position no-rethread harness and headrest adjust together easily with one hand, and the 9-position recline has an easy-read indicator to help you find the correct angle for your vehicle

Slide-Out Cup Holders: The dishwasher-safe cup holders slide out with ease for convenient cleaning and click back into place for a secure attachment during rides

Accessible Color-Coded Belt Paths: Make it easy to route the seat belt through the correct path for each car seat mode