Level 1 of the ECWCS system. Highly breathable moisture wicking, 4 ounce GI plus 100% polyester jersey knit fabric. Fabric helps wick moisture away from skin. Features PISOFT AB-500, durable anti-odor & anti microbial properties, improves elasticity & tear strength and pill resistant & anti-static. Military thermal top. Lightweight. Can be worn alone or as a base layer for extra warmth. Features: Long back tail, thumb hole sleeve. Black colored top. Military E.C.W.C.S. generation III silkweight underwear. Black - ECWCS generation III silk weight top.