The Wigwam Wind Break Arm Sleeve is a protective sleeve that's designed to enhance circulation, and provide warmth during long runs and bike rides. Made from a combination of Stretch Nylon, Dri-Release Wool, and Lycra, the F4000 dries extremely fast, and fits snugly on either arm. The Windbreak Arm Sleeve from Wigwam also features Freshguard Anti-Odor technology to keep your gear fresh.