Stay warm and dry to the core with Castelli’s ultra-soft Iride Seamless LS. While the inner, textured polypropylene fibers provide velvety comfort, their main purpose is transporting moisture from your skin to the outer nylon layer, speeding evaporation. This keeps you warm on cold rides by wicking dampness away on the climbs. Thumb loops hold the sleeves in place to keep that little strip of skin between your jersey and glove covered. Plus, the seamless design of the Iride might just make this the softest, most comfortable article of clothing in your cycling wardrobe.