After years of research and development, Troy Lee Designs introduced the A1 mountain bike helmet in 2013.This lightweight, fully encapsulated all-mountain helmet utilizes maximum coverage and dimension to keep you safe and protected in all riding conditions. Whether you\'re charging single track, riding dirt jumps or grinding out miles on the XC bike, the A1 helmet offers the premium fit, protection and style you want.   Key Features: Reinforced polycarbonate shell in-molded with the EPS liner extends down the sides and back of the head for maximum protection and durability, 8 pressurized intake passages draw in cool air for maximum ventilation, 8 rear vacuum vortex outlets help exhaust and draw heat from the head, Triple position adjustable retention system allows customized fit for various eyewear, head shape and riding styles, Single-piece, ultra-plush, removable and washable comfort liner made of anti-microbial moisture-wicking material for a dry, comfortable feel, Full-spectrum adjustable moto inspired visor with anodized aluminum hardware.