The mainly function of the over sleeves are sun block and cold-proof, in summer, it is better than sunscreen, after wear over sleeves, there is no hot and greasy feeling, but you will feel hot and greasy if you use sunscreen; Super elasticity, you can stretch freely; In winter, it can be cold-proof, keep your body warm; Size reference: 50~60kg: M, 60~70kg: L, 70~80kg: XL; 80~100kg: XXL; Suitable for both outdoor sports and daily use.