US M17 A1 A2 Gas Mask Outsert Eye lenses. The M17 Protective Mask is a series of gas masks that were designed and produced in 1959 (as a replacement of the M-9 gas mask) to provide protection from all types of known chemical and biological agents present. The M-17 was issued to troops in the Vietnam War, and was standard issue for the U.S. Military until it was replaced by the M40 Field Protective Mask for the U.S. Army and USMC in the mid 1990s while the U.S. Air Force and U.S. Navy replaced it for the MCU-2/P Gas Mask in the mid-1980s.
