Dual child weight ranges (4 to 22 lb. and 22 to 35 lb.) help to ensure infant car seat is reclined at the proper angle according to the weight of your child Height-adjustable Load Leg absorbs and distributes crash energy to the floor of the vehicle to reduce the forward pitching of the seat on impact, helping keep the child in the correct position during a crash Load leg also helps reduce the risk of injury that can be caused by the seat rotating too far forward on impact Solid steel spine creates metal to metal contact through the Load Leg, infant carrier, and the vehicle to add strength and properly manage crash forces Green safety button indicates a secure connection has been made between the infant car seat and the base The CYBEX Base 2 is for use with the Cybex Aton 2 Infant Car Seat. An additional base is ideal for multi-car families, allowing you to conveniently attach the infant car seat to the pre-installed base. Expanded assortment available online. This product is not available in our stores & may experience longer ship time. Please allow 10 to 14 days for this product to arrive.