Under Armour Boys' ColdGear Armour Up Mock 87% Polyester/13% Elastane Imported Fitted: Next-to-skin without the squeeze Dual-layer fabric with an ultra-warm, brushed interior & a slick, fast-drying exterior 4-way stretch fabrication allows greater mobility in any direction Moisture Transport System wicks sweat away from the body Anti-odor technology prevents the growth of odor-causing microbes