Stay comfortable when you're on a long hike or stalk, even in the hottest weather. HeatGear is made of a microfiber blend featuring Under Armour's signature Moisture Transport System. Wicks perspiration away and dries four times faster than cotton. Field-tested in simulated summer training-camp conditions, Under Armour garments kept the core body temperature of each wearer much cooler than subjects wearing cotton. This lightweight microfiber fits snugly. Imported.