PMEL: only the most precise will suffice
Senior Airman William Matlock, 437th Maintenance Squadron Precision Measurement Laboratory calibration technician, interprets data on a microwave measuring receiver at Joint Base Charleston, S.C. July 18, 2017. The receiver is used to calibrate communication systems and other frequency emitting instruments. Technicians calibrate, align, troubleshoot and repair test equipment and tools used at 11 Department of Defense installations. This practice is known as metrology, which is the science of weights and measures.