Under Armour Coldgear Infrared Thermo Quarter Zip Base Layer Top 4-Way Stretch fabrication allows greater mobility and maintains shape Bonded hex-patterned structure traps extreme heat without adding weight for unrivaled warmth ColdGear Infrared uses a soft, thermo-conductive inner coating to absorb and retain your own body heat Dual-layer fabric delivers a smooth, fast-drying exterior and soft interior Moisture Transport System wicks sweat away from the body