The Britax One4Life Convertible Infant Car Seat and Britax Poplar S Convertible Car Seat bundle offers two car seats to grow with your child from birth through the booster seat years. The One4Life convertible seat features four configurations, including a rear-facing infant seat supporting 5-40 lbs, a rear-facing toddler seat for 5-50 lbs, a forward-facing 5-point harness seat for 20-65 lbs, and a high back booster for 40-120 lbs with heights up to 63 inches. ClickTight installation, a steel frame, SafeCell technology, and a V-shaped tether provide safety assurances. Adjustments are easy with a 15-position headrest and no-rethread harness. Complementing the One4Life, the slim 17-inch Poplar S seat fits rear-facing up to 50 lbs and forward-facing starting at 22 lbs. It installs securely using ClickTight technology and offers a 14-position headrest and harness. Premium padding ensures comfort, while the flame-retardant fabric is safe to machine wash. With stages covering from birth to 10 years, these convertible Britax seats allow you to transport children safely and comfortably as they grow.