Airmen with the 374th Aircraft Maintenance Squadron perform checks to ensure they can receive water through their chemical, biological, radiological and nuclear protective gear during exercise Vigilant Ace 18, Dec. 6, 2017, at Yokota Air Base, Japan. The CBRN checks are to ensure the protective equipment is functioning properly and so airmen can stay hydrated while working in potentially contaminated conditions. (U.S. Air Force photo by Senior Airman Donald Hudson)