Chill-Its 6690 Cooling Arm Sleeves provide full arm coverage to absorb and wick away sweat, deliver advanced cooling relief, shield skin from the sun's UV rays, and even protect against light abrasions. Made with soft, lightweight performance knit fabric with UPF 50+ protection from harmful UV rays, these sun protective sleeves provide instant cooling relief when wet and wick moisture away when dry - helping absorb and dry sweat quickly. An anti-odor treatment keeps funky and unpleasant body odors under control when you're going all out. How to Activate Cooling & Wear Activation is easy. Simply run the cooling arm sleeves under cool water, then twirl or shake the sleeves to accelerate the chemical-free evaporative cooling process. Wear wet for cooling, or dry for moisture-wicking comfort. Enhance the cooling effects by wearing the sleeves on key pulse points (under arm and wrist). Sizing Thanks to its high-quality, high-elastic fabric, these unisex protective arm sleeves are suitable for most arm sizes - no uncomfortable pressure or discomfort. To determine the right sleeve size, just measure the circumference of your upper and lower arm and refer to the size chart for specific measurements of each size. Whether working outside or simply enjoying the outdoors (golfing, cycling, fishing, jogging, playing baseball etc), these uv sleeves provide great skin protection. Also perfect for covering up tattoos so as not to offend the prim and prudish with your gnarly ink.