Both the Maxi Cosi 2 Way Fix Base and BeSafe Izi Modular Base have front braces and support legs.
1. The front brace sits against the back of the back seat, sometimes called the lollipop, it provides stability and stops backward momentum. The BeSafe base has an adjustable front brace, which you can position further out from the base, so that when the car seat is in the rear facing position the child is sitting further towards the front of the car, with more leg room.
2. The support leg touches the floor of the car. It stops forward momentum in an accident, in the same way that a tether does.