While most arm coverings are designed to keep you warm, the UV- 50+ Light Arm Sleeves from Performance Endurance Gear can actually keep you cool too. They actually blocked 99.8 percent of damaging UV rays. It uses a polyester base that’s more effective than typical nylon at blocking UV rays while keeping you dry. Minimal seam construction prevents rubbing and single-sided silicone elastic at the openings ensure they stay in place throughout the ride. They also pack up extremely small so you can stash them into your jersey pocket when they’re no longer needed for the day.