Under Armour Boys' UA ColdGear Infrared Grid Hybrid Mock Dual-layer, textured-grid fabric traps heat for unrivaled warmth with very little weight ColdGear Infrared technology uses a soft, thermo conductive inner coating to absorb and 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