The Under Armour Boys' UA ColdGear Evo Fitted Mock Long Sleeve Running Top's EVO ColdGear® construction employs a dual layer material blend, whereby a smooth, fast-drying exterior membrane sheds water quickly and a brushed, insulative interior retains heat and maintains the wearer's temperature. The wearer's moisture output is managed by a Signature Moisture Transport System that wicks sweat away from the skin to encourage an interior environment that is also dry, as well as warm. A lightweight, 4-way stretch fabrication permits a full range of motion and unimpeded comfort, which, when coupled with a mock neck and anti-odour technology, works to deliver a garment that is simultaneously accommodating, insulative and fresh.