The Chicco KeyFit 30 Infant Car Seat is the premier infant carrier for safety, comfort, and convenience and accommodates infants from 4 to 30 lbs., up to 30". One-pull harness tightening and loosening allow for quick fitting, and the thickly-padded infant insert gives extra support for a smaller baby around the head, neck, back and bottom. The shell is lined with energy absorbing foam, and the vehicle base features an innovative UAS management system, easy belt routing, a one-pull, centrally located tightening strap and a spring-loaded leveling foot to make installation easy. The base also features a built-in belt locking system for vehicles without UAS and an enclosed underside to protect vehicle seats from damage. Proper installation is the key to safer travel, and Chicco's KeyFit is the easiest car seat to install correctly.