britax allegiance dimensions Britax Poplar Convertible Car Seat

britax allegiance dimensions Britax Poplar Convertible Car SeatBritax Poplar Convertible Car Seat Ready to gowith room to grow. The Britax Poplar Convertible Car Seat takes the guesswork out of moving up to the next stage. With its patented ClickTight Installation and ultra slim SpaceSaver design, it's made for easy, confident installs and a better fit in your back seat. This car seat supports extended rear facing up to 50 lbs, giving your child the safest ride for longer, and seamlessly transitions to forward

Britax Poplar Convertible Car Seat

Ready to go—with room to grow.

The Britax Poplar™ Convertible Car Seat takes the guesswork out of moving up to the next stage. With its patented ClickTight® Installation and ultra-slim SpaceSaver™ design, it's made for easy, confident installs and a better fit in your back seat. This car seat supports extended rear-facing up to 50 lbs, giving your child the safest ride for longer, and seamlessly transitions to forward-facing as they grow.

Why Parents Love It
✅ ClickTight® Installation – Install in 3 simple steps: open, thread & buckle, then click it closed
✅ Slim Yet Spacious – Just 17" across to help fit 3-across* without sacrificing comfort
✅ Extended Rear-Facing – Accommodates children up to 50 lbs and 49” in height
✅ Naturally Flame-Retardant Fabrics – Free from added FR chemicals and safe to machine wash and dry
✅ Peace of Mind Built-In – SafeCell® crumple zone, carbon steel frame, and V-shaped tether help manage crash energy effectively

Smart Safety Meets Everyday Convenience

• 14-Position Quick-Adjust Headrest & Harness – Easily adapts to your growing child

• 6-Position Recline – Ensures the most comfortable and secure fit in your vehicle

• SafeCell® Technology – Built-in crumple zone helps absorb crash forces

• Patented V-Shaped Tether – Minimizes seat rotation and forward movement

• Reinforced Carbon Steel Frame – Adds strength and stability

• 5-Point Safety Harness – Evenly distributes crash energy across strong bones

• Dishwasher-Safe Cup Holders – Removable and easy to clean

• Slim Design – Designed for easier 3-across fit in many vehicles*

Specifications

• Product Dimensions: 20.5" L × 17" W × 23.5" H

• Seat Area Depth/Width: 11" / 12"

• Shoulder Width: 14"

• Harness Slot Heights: 8" to 17" (14 positions)

• Buckle Strap Depths: 4" – 7"

• Rear-Facing Use: 5–50 lbs, under 49"

• Forward-Facing Use: 22–65 lbs, under 49"

Britax Recommends

• Always keep children rear-facing as long as possible, up to the maximum height or weight limit

• Use the 5-point harness until your child outgrows it by height or weight

• Always secure the top tether when installing forward-facing

Note: Britax cannot guarantee 3-across fitment in all vehicles. Always check fit prior to purchase.