US Military Brown Flame Resistant Silk Weight Base Layer Thermal Top Size Large Excellent conditon, very little signs of wear, no visible signs of flaws. Measurements are listed in the photos. See pics for more details The Military Issued USMC FROG (Flame Resistant Organizational Gear) is a Cold Weather Base Layer Thermal shirt that is part of the military cold weather clothing system (ECWCS). Manufactured by XGO for the USMC, it was designed to be a base layer thermal shirt worn next to the skin to wick perspiration and keep you warm while also being no-drip-no-melt flash fire resistant for safety. Base Layer Thermals are used in all layering system as your first defense against cold in temperate weather. A perfect thermal tee for those not just in combat but everyday work and active use especially where no-drip-no-melt is a safety need. Silk Base Layer Thermals are best worn snug so when temperatures drop you can layer over it. USA made; FROG Thermals have proven to work.