HeatGear Armour, our high-performance original baselayer, is the first thing you put on and the last thing you take off. That's why we've made it extra comfortable. The material wicks away sweat and stretches so you can move freely. The lightweight HeatGear fabric offers good coverage but is still light. Mesh inserts under the arms and on the back provide strategic ventilation. The material wicks away sweat and dries very quickly. Ergonomic design with seams outside high-wear areas for added durability. Hybrid raglan sleeve design offers greater freedom of movement and comfort.