Elizabeth Maschmeyer, 3rd Maintenance Squadron Precision Measurement Equipment Laboratory calibration technician, calibrates a sound system at Joint Base Elmendorf-Richardson, Alaska, Oct. 23, 2017. Technicians from the 3rd MXS PMEL can calibrate and repair Test Measurement and Diagnostic Equipment to accuracies ranging from millionths of an inch to microvolts, depending upon the measurement area. They do so with four criteria in mind: accuracy, reliability, traceability and safety.