UA CoolSwitch uses an exclusive coating on the inside that pulls heat away from your skin, so you actually feel cooler. Breathable ArmourVent mesh back panel is ultra-durable & delivers superior ventilation. 4-way stretch construction moves better in every direction. Material wicks sweat & dries really fast . Anti-odor technology prevents the growth of odor-causing microbes. Smooth, chafe-free flatlock seam construction.