What Makes the Castelli UPF 50 + Light Arm 3 Sleeves the Smart Choice for Sunny Rides?

The Castelli UPF 50 + Light Arm 3 Sleeves use a polyester-based Solare fabric that Castelli's lab tested at blocking 99.8 percent of damaging UV rays. The fabric is more effective than nylon at stopping UV while doing a much better job of moving moisture, which means you stay drier and cooler when the sun is on you. Construction is kept clean to eliminate seams that can rub on long days.

A double-sided silicone elastic at the top keeps each sleeve locked in place against your skin and grips the inside of your jersey sleeve so nothing slides as you ride. At only 57 grams for the pair and rated for 50 to 64 degrees F, they pack down small enough to stash in a jersey pocket when the sun goes behind a cloud or you finish your climb.