The reasons for slipping on Giro's Chrono UV Arm Sleeves before a ride are as numerous as the skin cells they cover up. Being a cyclist entails spending an inordinate amount of time in the sun, with training sessions, century rides, and races routinely extending our exposure from five to 10 hours at a time. We owe it to our skin and our future health to alleviate the potential for damage, and the Chrono UV Arm Sleeves provide UPF 50 protection to reduce the harmful UV rays hitting our skin. ,p>While they're not as light and airy as riding with bare arms, they're still light enough for all conditions but the most sweltering summer days, and their high-stretch synthetic material and spiral knit construction efficiently wicks moisture, keeping you free from soggy slop and the sun's punishment simultaneously.