Eastbay EVAPOR Arm Sleeve - Men's The Eastbay Arm Sleeve is designed as a support layer to help keep muscles warm. EVAPORô permanent moisture-management fabric wicks unwanted moisture to the surface to be evaporated, leaving you cool, dry and ready for more. It also offers a layer of protection against minor skin abrasions. 170 gram 84% polyester/16% spandex. Sold individually. Imported.