U.S. Air Force Airman 1st Class Keanu Alderson, 20th Equipment Maintenance Squadron armament maintenance journeyman, performs an inspection on a M61A1 Vulcan 20 mm rotary cannon transfer unit shaft at Shaw Air Force Base, S.C., Aug. 2, 2018. The transfer unit shaft assists in feeding bullets into the Vulcan and extracts the shells after firing. (U.S. Air Force photo by Senior Airman Christopher Maldonado)