A1 might normally remind you of steak, but in this instance we are talking all-mountain bike helmets. The Troy Lee Designs A1 MIPS Bike Helmet is built for balance. It's polycarbonate shell with EPS core bridges the gap between coverage and comfort for added protection when the trail gets steep and the triple fit support system keep this bucket locked in place, eyewear or not. From dirt jumps to the mountain top, the Troy Lee Designs A1 MIPS Bike Helmet is built to ride.