Cooler, Faster In a Protective Package. The trailblazing A2 is Troy Lee Designs’ mountain bike trail helmet that checks all the boxes. Its stylish shell not only incorporates huge intake and exhaust ventilation ports, but it also comes with the very best in impact protection. From breakaway visor screws and the innovative MIPS® system and an industry-first dual-density EPP + EPS liner that protects against both high and low-speed impacts; this is a helmet that doesn’t take your safety lightly. Add in an adjustable strap and X-Static® Pure Silver comfort liner and the comfort is every bit on par with the protection.