Under Armour Men's UA ColdGear Infrared Grid Crew Dual-layer, textured-grid fabric traps heat with very little weight ColdGear Infrared technology uses a soft, thermo-conductive inner coating to absorb & retain your own body heat Moisture Transport System wicks sweat away from the body Anti-odor technology prevents the growth of odor causing microbes Smooth, chafe-free flatlock seam construction