Solocc cycling sun sleeves are constructed from Xylitol impregnated Ice-fil® fabric. Xylitol converts sweat to refrigerant. Amazingly, your arms will be 1-3 degrees cooler when wearing these compared to bare arms. In addition, the coolers have a UPF (Ultraviolet Protection Factor) of 50+. Multi-panel construction, flat-lock stitching and soft gripper elastic means these are amongst the most comfortable arm coolers available. They have an anatomic cut and are left and right arm specific.