A U.S. Army Ranger displays his connector regulator unit-60/P as a hypobaric altitude chamber instructor goes over what the 60/P is used for and how to use it at Langley Air Force Base, Va., Nov. 14, 2014. The 60/P connects the oxygen mask to the supply hose or emergency high pressure system. (U.S. Air Force photo by Staff Sgt. Natasha Stannard/Released)