On or off the bike the Giro Merino Wool Cap is a cyclist's staple. The wool cap insulates to keep your head warm but the X-Static liner breathes well and wicks moisture away from your skin. It's substantial enough to wear alone off the bike and thin enough to wear under your helmet for a little extra warmth. Merino also fights odor so it won't stink even after sweaty rides. Giro also added ear flaps that fold up or down for added protection and a short reinforced brim to keep rain and sun out of your eyes.