SHAW AIR FORCE BASE, S.C. --   Precision measurement equipment laboratory Airmen spend their day taking measurements with various tools to ensure the readiness and accuracy of the U.S. Air Force. The 20th Component Maintenance Squadron PMEL flight calibrates approximately 9,500 different types of equipment, using their own equipment to adjust a tool until an appropriate measurement is read. The 20th CMS PMEL flight assists the missions of approximately 193 work centers from across nine active-duty bases, including the 20th Fighter Wing, three Air National Guard bases and the Department of Homeland Security.