North Safety emergency escape mouthpiece respirator is easy to use and only weighs 7 ounces. Completely disposable eliminating the need for a maintenance program. Lightweight, low breathing resistance, break away noseclip and neck strap, may be clipped on a belt using the large stainless steel belt clip. The 7902 is NIOSH approved protection during escape only from atmospheres containing Chlorine, Hydrogen Chloride, Hydrogen Sulfide, Chorine Dioxide and Sulfur Dioxide. The 7904 is NIOSH approved for respiratory protection during escape only from atmospheres containing ammonia. Optional storage carrybag available. 10 per case. Sold by the each.