3 Modes of Use: Booster #1 is with the internal front adjust 5 point harness that is rated from 22 to 40lbs with a extra deep headrest area for added support and comfort. Booster #2 is a belt positioning booster for children 40 to 100lbs. and the headrest has three positions to grow with your child. The arms fold up and down on each side and two integrated cup holders can accommodate drinks or snacks. Booster #3 is a backless version of #2 and you keep the armrests, cup holders and weight range but with the back removed the booster moves easily from vehicle to vehicle.