"Based on feedback from more than 50 athletes UV shielding rate 94% protects your arms from the sun. No tightness, so easy & natural fit, you would forget about being wearing them. Light and comfortably soft texture, superb moisture absorption, and quick dry. The longer length cover your arm up to under your T-shirts sleeves. Special sustainable eco-polyester, ultra-fine polyester nanofibers provide a strong but comfortable gripping, preventing the tubes to slip down. Seamless tube means no irritation with a bulky seam. Cool in summer because of the vaporization heat, and warm in winter because of the layers of warm air. Cool design adds a tasteful touch to your usual sport outfit. Extra warmth would be appreciated at the scene of highland hike in summer or night trail run. Once it gets too warm, simply pull it down to the wrist, handy to wipe your sweat on your face. Size (flat) S 42cm 21g/pair, M 47cm 24g/pair, 52cm 26g/pair 94% UV protection Composition: polyester 78% nylon 17%, polyurethane 15% We use sustainable eco-polyester Made in Japan, Koryo, the Town of Socks"