The Keysight / Agilent / HP 8487A thermocouple power sensor is designed for use with the EPM series, EPM-P series, 70100A, E1416A and the 43x series power meters, and provides extraordinary accuracy and stability. The 8487A power sensor also gives you extremely low SWR even at mm-wave frequencies. This calibration eliminates the uncertainties due to temperature changes and the variance in making measurements with different meter/sensor combinations.