Under Armour HeatGear Sonic Fitted Short Sleeve Running T-Shirt UA HeatGear Fabric - Wicks away sweat to keep feet cool, dry, and light. 4-Way Stretch Fabrication - Allows for greater mobility and maintains its shape. Signature Moisture Transport System - Wicks sweat away from the body, keeping you cooler and drier. Anti-Odour Technology - Prevents the growth of odour causing microbes. Smooth Flatlock Seams - Allow a full range of motion without chafing.