Senior Airman Nishit Macwan, 741st Maintenance Squadron power, refrigeration and electrical laboratory technician, troubleshoots a missile alert facility chiller during the Global Strike Challenge July 26, 2021, at Malmstrom Air Force Base, Mont. PREL Airmen are specialists in electrical and refrigeration troubleshooting and repair. (U.S. Air Force photo by Airman Elijah Van Zandt)