U.S. Navy Diaphragm Optical Mark 1
Country |
United States of America |
Use |
Military |
Years produced |
1940's |
Filter Thread |
Fixed |
Label on underside of the filter.
"WARNING: The purpose of this canister is to purify under open air conditions, air containing irritants and poisonous gases and smokes used as chemical warfare agents.
DO NOT USE Against ammonia, carbon monoxide, illuminating gas, mine gasses, when fighting fire in closed spaces, in mine rescue work, in fumigating work, in semi-closed or closed spaces (tanks, etc.) containing volatile liquids, in places where large quantities of of gas or vapor have been released so as to build in concentrations of one or more percent by volume in air, in any place where the oxygen content is so low that a safety lamp will not burn.
Mine Safety Appliance Company"