The Britax extra base provides ultimate travel flexibility in multiple vehicles. Drop in design make it simple to place the car seat into the base for easy and secure traveling. Safe-center latch installation creates peace of mind by making it easy to install the base correctly. The impact absorbing base absorbs crash energy and our impact stabilizing steel frame gives strength where you want it most. Premium features like easy-on/easy-off latch connectors, spring-assisted recline and dual level indicators make installing and setting the proper installation angle simple and easy. This product is compatible with the B-Safe 35 and B-Safe 35 elite.