2011 Gas Mask Test
U.S. Air Force Staff Sgt. Bryan Stewart, 20th Civil Engineer Squadron readiness apprentice, connects the M50 mask for gas mask testing , Shaw Air Force Base, S.C., Oct. 20, 2011. The M50 mask replaced the MCU-2/P gas mask to improve breathing resistance and field of view. (U.S. Air Force photo by Airman 1st Class Ashley L. Gardner/ Released)