NecksGen Wedge Helmet Supports feature a soft foam design to fit with your REV Head and Neck Restraint, this frontal collar helps stabilize your head and helmet to prevent fatigue and neck strain over long endurance races or off-road races with rough terrain. The washable SFI 3.3 rated cover has an adjustable hook and loop flap at the back so you can adjust your support for the most comfortable fit.