Under Armour Men's HeatGear CoolSwitch Fitted Short Sleeve 90% Polyester/10% Elastane Imported UA CoolSwitch uses an exclusive coating on the inside that pulls heat away from your skin, so you actually feel cooler Allover mesh fabric for superior ventilation & breathability 4-way stretch construction moves better in every direction Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes