With clean looks, high muscle support and UV protection, the Castelli UPF 50+ Light Arm Skins have a seamless design for a silky-smooth feel against the skin. Polyester base is more effective than nylon at blocking UV rays and keeps you drier for comfort in cooler and warmer conditions. Solare fabric takes the edge off chilly rides. No-seams mean no chafing and double-sided silicone elastic bands keep the arm skins in place. Arm Skins fold up extremely small, so they can be stashed in a pocket while riding.