Under Armour Men's CoolSwitch Run Long Sleeve 100% Polyester Imported UA CoolSwitch uses an exclusive coating on the inside that pulls heat away from your skin, making you actually feel cool & able to perform longer Mesh back & underarm panels deliver strategic ventilation 4-way stretch fabrication allows greater mobility in any direction Moisture Transport System wicks sweat & dries fast Anti-odor technology prevents the growth of odor-causing microbes