The Hot Chillys Men's Pepper Skins Crewneck Top is your standard, dependable thermal underwear. This base layer shirt features Hot Chillys staple MTF polyester fibers, which work to transport moisture away from the skin as you go about your day. The Hot Chillys Men's Pepper Skins Crewneck Top features a flat seam construction for seam strength, durability, and longevity and a relaxed fit for everyday comfortable use.