Techniche Kewlshirt Tank Top, Gender: Mens/Unisex, Primary Color: Black, Size: Md, Distinct Name: Black 6201BKM Traditional tank top styling, made with spandex, Hyperkewl fabric and waterproof nylon Designed to be worn against the skin for maximum cooling effect, with ventilation vents built into back and front panels Best worn underneath a breathable sport jersey or on its own Can provide 5-10 hours of cooling relief per soaking Lightweight, easy to activate, and durable