M2 gas mask

The M2 gas mask was a French-made gas mask used by French, British and American forces from April 1916 to August 1918 during World War I. The M2 was fabricated in large quantities, with about 29,300,000 being made during the war. It was intended to protect the wearer from at least five hours' exposure to phosgene gas, a common chemical weapon of the time.