The car seat portion of your travel system must be securely fixed in your car. The vast majority of Britax car seats come with a base that you can keep fixed in place in your car, allowing you to simply click the seat in place on top of it, which saves the hassle of manually fixing it in place each time. However, you can also choose to use the LATCH system, assuming your car is compatible with it (as are nearly all vehicles made after September 1, 2002).