The Agilent ECP-E26A is a CW Power Sensor. Same as the E4413A The E4413A diode Power Sensor, with wide dynamic range, is designed for use with the EPM and EPM-P series power meters for power measurements on CW signals from 50MHz to 26.5GHz. The E4413A power sensor provides extremely low SWR to minimize the source and sensor mismatch errors. Also, for comprehensive error correction, the calibration factors, linearity and temperature error-correction information are stored in EEPROM.