Under Armour Boys' ColdGear Armour Up Printed Mock 90% Polyester/10% Elastane Imported Dual-layer fabric with an ultra-warm, brushed interior & a smooth, fast-drying exterior 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 Smooth, chafe-free flatlock seam construction