You don't stop riding just because it's cold, do you? We didn't think so, and neither did Fox. Their 82% polyester/18% spandex Helmet Liner fits snugly under your helmet and keeps your noggin warm on those off-season rides. It's breathes well and dries quickly so you stay the right temp, it's also small and light enough that it should never leave your pack. Unless it's on your head.