This prevents the visor snagging on objects which can wrench your neck and cause injury

70mm Stem Clamp Width

Bearing: 4 sealed bearing

then read on

Fox Speedframe Pro Helmet 25 - M - Black Heavy/Bulky This prevents the visor snaggingPart of Greg Minnaar's signature trail collection, with subtle nods to his victories and achievements throughout his career. The Speedframe Pro Helmet earned Virginia Techs best rating (5 STARS) in its Bicycle Helmet Ratings program. Designed with input from our pro mountain bike athletes, this top tier open face mountain bike helmet offers a market leading feature set. Mips equipped Virginia Tech 5 star helmet rating Goggle compatible, 3 position