Level Two of the ECWCS (Extended Cold Weather Clothing System)  Mid-Weight Thermal Shirts are an essential base layer for military and tactical professionals.  The highly breathable, moisture-wicking polyester and spandex material is designed to protect from the harshest elements. Mid-weight underwear tops feature a zip up collar, long back tail, and thumbholes in the sleeves for maximum comfort and fit. The grid fleece fabric is anti-odor and anti-microbial for long-lasting wear.