HeatGearA(R) Armour is our original performance baselayer-the one you put on first and take off last. So we made it extra comfortable by wicking sweat and stretching so you can move no matter what. Features and Specifications: Super-light HeatGearA(R) fabric delivers superior coverage without weighing you down Mesh underarm & back panels for strategic ventilation Material wicks sweat & dries really fast Anti-odor technology prevents the growth of odor-causing microbes Ergonomic design keeps seams off high abrasion areas & increases durability Hybrid raglan sleeve construction for added range of motion & comfort