Troy Lee D4 Composite Race Helmet - Stealth GreyBuilt with an aerospace shell design and materials, Troy Lee were able to get the D4 Composite helmet to 1050 grams without sacrificing any strength. MIPS (multi directional impact 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 centre and power grid side mesh keeping your head cooler during the ride. X