These highly breathable, moisture-wicking, lightweight undergarments are quality-constructed from 3.7 ounce performance plus 100% polyester plaited jersey knit, a virtual match of the current military version. The fabric literally "wick" moisture away from the skin to the outer layers of the clothing, making these lightweight garments extremely popular all-day garments that provide great warmth without weight, quick drying and easy packability. As an enhancement of the military garments, all of the Tru-Spec level 1 garments are constructed with Microban, a powerful anti-microbial and odor-fighting agent that is added at the time of manufacture.