U.S. Air Force Staff Sgt. Dylan Crump, 1st Operations Group aerospace and operational physiology technician, watches vitals on the Reduced Oxygen Breathing Device at 1st OG AOP, Joint Base Langley-Eustis, Va., Dec. 5, 2017. The ROBD is a machine that is used to simulate high altitude exposure environments to induce hypoxia symptoms so that the individuals practice recognizing the symptoms. (U.S. Air Force photo by Airman 1st Class Tristan Biese)