Altitude chamber
Senior Airman Devin Theis instructs Airmen on the proper use of an oxygen mask during altitude training Dec. 8, 2014, at Little Rock Air Force Base, Ark. Students undergo hypobaric chamber training to experience the effects high altitude has on the body, which include low oxygen levels. Theis is a 19th Aerospace Medicine Squadron high altitude airdrop missions technician. (U.S. Air Force photo/Airman 1st Class Harry Brexel)