Under Armour CoolSwitch Compression T-Shirt - SS16 HeatGear Sonic Fabric  Smooth, lightweight fabric construction providing comfort and compression. 4-Way Stretch Fabrication  Allows greater mobility in any direction. Signature Moisture Transport System  Helps wicking sweat away and dries fast. Anti-Odour Technology  Prevents the growth of odour-causing microbes. Flatlock Seam Construction  For a smooth, chafe-free motion and fit.