FR 5.5-ounce knit: 55% Modacryllic, 40% Tencil and 5% Spandex. Intended as a base layer. Wicking technology with Anti-Odor control. Meets NFPA 70E standards. Stretchable, spandex-rib-knit fabric for comfort. Side-seamed construction minimizes twisting. Square hem. Carhartt FR and HRC 1 labels sewn on side-seam. Flame-resistant fabric by Innovative Textiles, Inc. VPN: FRK009.