The Tru-Spec Gen III Level 1 ECWCS Undershirt is an upper body base layer, based closely on the United States Military's current Extreme Cold Weather Clothing System. It is made from a polyester jersey knit fabric that traps warm air against the skin while also wicking away sweat effectively, keeping you both warm and dry in cold conditions. Built-in Microban anti-microbial technology keeps odor-causing bacteria at bay, keeping it smelling fresh for longer. The sleeve thumbholes improve wrist and hand coverage, while the flatlocked seams and tagless design eliminate chafing. Reinforced double needle stitching at the collar and hem improves durability.