Under Armour Boys' ColdGear Infrared Long Sleeve 100% Polyester Imported Loose: Fuller cut for complete comfort ColdGear Infrared technology uses a soft, thermo-conductive inner coating to absorb & retain your own body heat Two-tone, closed-hole mesh fabric is lightweight & incredibly breathable Moisture Transport System wicks sweat & dries fast Anti-odor technology prevents the growth of odor-causing microbes