It wasn't easy to improve upon the class-leading design and function of the D3 helmet, but Troy Lee made it happen. Built with an aerospace shell design and materials, they 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. 20 high-flow intake and exhaust ports for maximum ventilation. Added eps and new headform shape for improved impact performance. Full incremental sizing for greater range of fitment. Strategically placed interior chinbar shock pads for comfort and durability. Quick-release and contoured 3D cheek pads for emergency helmet removal. Ionic+ comfort liner Purpose-built internal cavities for audio integration. Stainless steel chinstrap D-rings are light and strong. Includes TLD drawstring helmet sock. Exceeds bicycle certifications: CPSC 1203, CE EN 1078:2002+A1:2012 ASTM F1952-15, ASTM F2032-15, ASTM F2040-11. Not intended for use with motorized vehicles.