Part of the USMC FROG (Flame Resistant Organizational Gear) Program, this next-to-skin underwear layer is designed by XGO and made by various government contractors for the military.

The undershirt is a mock turtleneck undershirt with long sleeves and self fabric cuffs. The underwear is in a silk weight modacrylic/rayon blend material. The fabric is quick drying, moisture wicking, and includes antimicrobial properties.

They provide improved moisture management and comfort when worn in intermediate to cold weather environments. In addition, it will provide FR protection when needed. The FR Silkweight Underwear can be worn as part of the Mountain Cold Weather Clothing System (MCWCS) or Flame Resistant Organizational Gear (FROG). Replaces Desert Tan models.