Under Armour Men's ColdGear Armour Insulated Compression Mock 87% Polyester/13% Elastane Imported Compression: Ultra-tight, second skin fit UA Storm technology repels water without sacrificing breathability Strategically placed 101g Polartec Alpha insulation is extremely breathable & exceptionally warm Dual-layer fabric with an ultra-warm, brushed interior & a slick, fast-drying exterior 4-way stretch fabrication allows greater mobility in any direction