The Under Armour HeatGear Sonic Compression Half-Sleeve top wicks moisture away from your body to the outer layer of the shirt to keep you cool, dry, and comfortable. Features superior four-way stretch fabric that provides performance without restriction. Anti-odor technology keeps your gear fresher, longer. Smooth flatlock seams allow a full range of motion without chafing. HeatGearŪ works best in weather between 75 and 100 degrees. 84% polyester/16% spandex. Imported.