With our new a1 helmet we at troy lee designs are proud to introduce our resounding return into the aggressive all mountain half shell category reinforced polycarbonate shell in molded with the eps liner extends down the sides and back of the head for maximum protection and durability mips brain protection system reduces rotational forces to the brain 8 pressurized intake passages draw in cool air for maximum ventilation 8 rear vacuum vortex outlets help exhaust and draw heat from head triple