The Marathon ClickTight convertible car seat has the patented ClickTight Installation System, a layer of side impact protection, and SafeCell Impact Protection for peace of mind while you're on the go with your child. Car seat installation is easy as buckling a seatbelt thanks to the ClickTight Installation System. In the Marathon Car Seat you are surrounded in safety. This convertible car seat features the patented Britax SafeCell Impact Protection system which includes a steel frame, energy-absorbing base, V-shaped tether to minimize seat rotation and staged-release stitches that slow and reduce forward movement in the event of a crash. Britax designed the Marathon ClickTight Car Seat with a strong layer of side energy absorption; a deep foam-lined shell will shield your child from side impacts. Plush foam padding and fabric, along with 7 recline positions ensures premium comfort for your child. The 14-position easy-adjust harness grows along with your child and you can change the height of the seat with just the push of a button - no rethreading necessary. The Marathon car seat can be used rear-facing 5-40 pounds and forward-facing 20-65 pounds, child standing height 49” or less. Car seat dimensions 23” D x 18.5” W x 23.5” H. 14-Position harness slot heights 8.35” to 17.7”. FAA approved.