Under Armour: The Advantage is Undeniable.? Just because you have to hunt in the heat doesn't mean you have to hunt hot. Spring through fall, HeatGear optimizes your core temperature. Wear on its own, or as a loose-fitting base layer. HeatGear Loose Fit answered the call from the field: give us moisture management and core temperature regulation in a generous cut for comfort. Lightweight and versatile, HeatGear works under your outerwear or on its own to deliver the signature Moisture Transport System comfort through spring, summer, and fall. Ultimate comfort, with a great fit. Provides a full range of motion for periods of high activity, in addition to its exceptional Moisture Transport System wicking properties. Embedded in the fibers, Armour Block? prevents the growth of bacteria to combat odor in the most extreme weather conditions. Machine wash. Imported. New color Digital (B) will not be available until July 2007.