Dual-layer fabric with an ultra-warm, brushed interior & a smooth, fast-drying exterior Stretch-mesh back & underarm panels provide strategic ventilation without sacrificing warmth 4-way stretch material moves better in every direction Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes Ergonomic design keeps seams off of high abrasion areas Mock neck construction for added coverage & warmth We all hate it. That stiff, distracted feeling you get when you're out in the cold. That's why, UA built a baselayer that keeps you warm and dry without being bulky or riding up, so you can stay focused all season long.