DPM Elements are designed to be used with the 5010 Series, Digital Power Sensors. Using familiar form element design, the DPM Element can accurately measure true average power. All Plug-In Elements are calibrated in accordance with meticulous Bird calibration procedures supported by a long history of mean deviation values to assure adherence to advertised specifications of current instruments, as well as field interchangeability with equipment purchased, used and trusted in all the years since its introduction.