Staff Sgt. Prince Johnson
U.S. Air Force Staff Sgt. Prince Johnson, 51st Security Forces Squadron Defender, dons his gas mask during a field training exercise at Osan Air Base, Republic of Korea, March 23, 2017. Johnson was part of a group of Defenders who went through the 51st SFS Combat Readiness Course, a 10-day program that covers basic and advanced contingency operations and base-specific defense tactics, including the use of Mission Oriented Protective Posture gear.
(U.S. Air Force photo by Staff Sgt. Victor J. Caputo)