White, Navy, BlackThermastat is 100% polyester 170gsm hollow core fabric from Dupont. The hollow core affords more warmth than conventional thermalwear, and is super soft next to te skin. This garment has high wickability and is non absorbent - which means it draws moisture away from the skinand doesn't smell if you wear it longer than a day. Sizes: Xsmall - XXXlarge