Under Armour Heatgear Sonic S/S T-Shirt - Women's The Under Armour HG Sonic T-Shirt features HeatGearŪ moisture-management technology that works to keep your skin cool and dry. The fabric is lightweight and stretchy, allowing for great flexibility. Anti-odor technology works to keep you smelling fresh. HeatGearŪ is best for weather between 75-100 degrees. Fitted fit. 90% polyester/10% spandex. Imported.