Duofold Men's Mid Weight Thermal Underwear Set + Free Sock Long-sleeve crew neck shirt and ankle length bottom + FREE crew sock. Choose thisthermal setfor everyday warmth during low activity levels. Close-to-body fit. Ideal on its own or as base-layer underwear. Ankle length bottom features a front fly and chill-blocking cuffs. 2 layer texture knit traps air for a chill-blocking barrier to add warmth.