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’s designed to grow with your child for up to 10 years. It starts rear-facing with an extended capacity of up to 50 lbs, so your child can ride rear-facing longer. It easily converts to forward-facing toddler mode (up to 65 lbs) and high-back, belt-positioning booster mode (up to 120 lbs) when your child is ready.

With a slim outside and spacious inside, the 17.5” seat is designed to fit 3 across* without compromising safety and comfort. ClickTight helps you install with confidence, every time. The base and shell are easy to wipe down for hassle-free cleanup. The car seat cover is safe to machine wash and dry, and it’s naturally flame-retardant with no added FR chemicals.

One4Life Slim features 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, three infant inserts, and built-in armrests, your child will love every ride. *Britax cannot guarantee 3-across fitment in all vehicles.

• ONE CAR SEAT FOR LIFE: Designed to grow with your child for 10 years, this all-in-one car seat easily converts from a rear-facing infant and toddler car seat (5-50 lbs) to a forward-facing car seat with a harness (30-65 lbs) and, finally, to a high-back booster (40-120 lbs). 
• FAST, SECURE, & PARET-FRIENDLY INSTALLATION: With ClickTight® technology, you can install with confidence in 3 easy steps: pinch to open, thread and buckle, click it closed. 
• SLIM 17.5” SPACESAVER­™ SEAT: Designed to fit 3 across* without compromising on trusted Britax safety or premium comfort, offering a slim outside and spacious inside. *Britax cannot guarantee 3-across installation fitment in all vehicles. 
• EXTENDED REAR-FACING CAPACITY: Accommodates children up to 50 lbs and 49” rear-facing, so your child can ride rear-facing longer. 
• HIGH-STRENGTH STEEL FRAME: Reinforces the seat structure to help keep it sturdy and stabilized. 
• SAFECELL® TECHNOLOGY: Acts as a crumple zone, absorbing crash energy to help keep it away from your child. 
• TWO LAYERS OF ENERGY MANAGEMENT: The protective seat shell and foam-lined headrest help absorb impact energy and are designed to help keep your child's head, neck, and body safe. 
• TRUSTED BRITAX SAFETY: This seat is side-impact tested according to FMVSS 213a.* It is also tested to FMVSS 213 frontal-impact standards. *FMVSS 213a sets side-impact standards for children up to 40 lbs and 43” with a 5-point harness. It does NOT include standards for testing harnessed children above 40 lbs and 43” or for booster mode.    
• PATENTED V-SHAPED TETHER WITH STAGED-RELEASE STITCHES: Helps slow and reduce forward movement during a crash. 
• NATURALLY FLAME-RETARDANT CAR SEAT COVER: With no added FR chemicals.      
• SAFEWASH® FABRICS: No more hand-washing or waiting for the cover to air-dry. Just quick and easy cleanup so you can keep moving. 
• EASY-ADJUST, 15-POSITION, NO-RETHREAD HARNESS: One-hand adjustments make it easy to find the right fit for your child as they grow. The 15-position harness and headrest move together easily – no rethreading required. 
• QUICK-PUSH, 9-POSITION RECLINE: With easy-read indicator to help you find the correct angle for your vehicle. 
• 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. 
• TIMELESS, SOPHISTICATED AESTHETIC: Features soft knit fabrics in warm, neutral fashions with woven mélange accents that are made from recycled polyester. 
• THREE REMOVABLE INFANT INSERTS: Help provide a better fit for infants 20 lbs and under. 
• ACCESSIBLE COLOR-CODED BELT PATHS: Make it easy to route the seat belt through the correct path for each car seat mode. 
• 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. 
• CUP-HOLDER-FREE OPTION: Remove the cup holders completely and insert the armrest caps to save additional space. 
• SOFT COMFORT PADS: Help prevent the harness from rubbing against your child’s skin. 
• FLIP-FORWARD BUCKLE PAD: Stays out of the way for easy boarding; made with extra padding for premium comfort. 
• BUILT-IN COOLING CHANNELS: Improve airflow to help keep your child comfortable. 
• PLUSH PADDING: For superior comfort and a quiet ride. 
• EASY-PULL HARNESS ADJUSTER: Lets you tighten the harness using just one hand. 
• HARNESS HOLDER SLOTS: Keep the harness straps out of the way while your child gets in and out of the seat.  
• 5-POINT SAFETY HARNESS WITH DIAMOND WEAVE WEBBING: Provides adjustment points at the hips, shoulders, and between the legs. 
• TAG-FREE HEADREST: Supports your child’s head and neck without irritation. 
• BABY SAFETY ALLIANCE VERIFIED: The One4Life Slim is verified by the Baby Safety Alliance.