One of the most successful Masks ever developed by the U.S. military, the M9 Series Field Mask was in use during the hottest parts (1950-1970's) of the Cold War. First used by infantry during early chemical weapons and nuclear fallout defense training. Later seen worn by decontamination crews and chemical inspectors during WMD monitoring programs up through the 1990's. This is a Cold War-era Mask, still sealed tight in the original tin. In storage for decades, each is sure to show signs of age. A real piece of history!