Liquid Oxygen
Staff Sgt. Austin Klein, 180th Fighter Wing crew chief, services a liquid oxygen bottle for an F-16 Fighting Falcon during exercise Northern Lightning at Volk Field in Camp Douglas, Wis., Aug. 7, 2023. Northern Lightning is a joint training exercise emphasizing user-defined objectives resulting in tailored, scenario-based, full spectrum training. (U.S. Air National Guard photo by Airman 1st Class Sarah Stalder Lundgren)