Trek Ballista MIPS Road Bike HelmetTrek Ballista MIPS Road Bike Helmet Less wind. More win. When speed is your top priority and every watt counts, reach for the helmet that'll cut through the wind to save you seconds. Ballista is Trek's fastest, most aerodynamically advanced helmet. The Ballista is light, cool, comfortable and engineered with a fully integrated Mips Air safety system that's designed to help keep you safer. Features: Trek's fastest, most aerodynamic helmet will save big