ARC FLASH & FLAME RESISTANT FOR LIFE – This 5.2 oz material is a soft, inherent blend of Modacrylic, Cotton and Nylon. They will remain arc and flame retardant regardless of the washes and wear cycles. These neck gaiters, or face masks, are NFPA 70E Compliant, HRC / CAT 1, EBT = 6.4 cal/sq-cm and meet ASTM F1506. Don’t add fuel to the fire in the event of an arc flash or flash fire. One Size Fits All. These FR neck gaiters have an asymmetrical, stretchable rib panel so it can fit any size head.