Polyester<br>1.UPF 50+ PROTECTION: Our sunblock arm sleeves are made of the highest-quality and lightweight polyester fiber material. They can block out as high as 98% of harmful UVA and UVB rays to prevent sunburn, skin aging. You are maximum all-around UV protected all day long in any hot weather. They are prefect for outdoor activities: running, golfing, fishing, playing basketball, cycling, hiking, driving and even gardening.<br>2.COMPRESSION SUPPORT: The protective sleeves can offer you great compression which will make you feel tight but not over to protect and support your arm. True compression that promotes blood circulation and oxygen flow, reduce muscle soreness. No matter what you do, the sports sleeves can give you the support you need.<br>3.EFFECTIVE PAIN RELIEF: The sleeves can deliver pain relief from muscle soreness, while boosting blood flow to aid recovery. It can be used as a lymph edema sleeve, tendinitis elbow brace, or to lessen pain from injury or medical problems in upper arm or forearm.<br>4.COMFORTABLE & BREATHABLE: The moisture-wicking fabric is breathable comfort, while cooling in the heat, warming in the cold. Great to keeping your hands drier when you sweat. Elastic upper cuff with anti-slip band has excellent stay-in-place performance. They help arm sleeves stay up well on your arms whatever you do. Do not rub, slip or annoy you.