If you weigh every part that goes on your bike to the closest gram, you're going to love Giro's Prolight helmet. Using Giro's In-Mold construction, the outer shell is fused with the impact-absorbing EPS liner, and each is reinforced by the other for superior strength and durability. The minimal Roc Loc SL retention system uses featherweight straps made from Italian webbing for a helmet so light and comfy, you'll forget you have it on. Set it once and the Roc Loc SL self-adjusts to provide a comfortable, secure fit. Twenty-five vents and a labyrinth of internal channels flush cool, fresh air around your head while forcing heat and stale air out like no other.