Always Evolving It wasn't easy to improve upon the class-leading design and function of our D3 helmet, but we made it happen. Built with an aerospace shell design and materials, we were able to get the D4 Composite helmet to 1050 grams without sacrificing any strength. MIPS C2 protection system is used to add an additional layer of safety in the event of a fall. For comfort, the D4 Comp routes cooling air through a front air intake system that flows through the polymer center and power grid side mesh keeping your head cooler during the ride. X-static® and XT2® anti-microbial/anti-odor padding keep the inside of the helmet a much nicer place to be. This helmet is designed and intended exclusively for use by bicycling activities, including mountain biking and off-road cycling.