The Black Stallion WF2110-ST FR Cotton Work Shirt is FR-treated cotton (100 washes) meets the NFPA 2112 standards for flash fire protection and NFPA 70E standards for arc flash hazard protection. And, it is tested to ASTM F1506 standards for flame resistance to maintain protection through 100 home washings. It is made of 7 oz. FR-treated cotton and stitched together with durable FR threads. Shatter proof FR melamine buttons remain durable, while keeping the shirt a generous comfortable fit. Chest pockets with flaps and pencil slot and a curved hem provides enhanced protection when shirt is untucked.