The Hewlett-Packard Model 432A Power Meter, with HP temperature-compensated thermistor mounts, measures RF power from 10 microwatts (-20 dBm) to 10 milliwatts (+10 dBm) full scale with 1% of full scale accuracy from 10 MHz to 40 GHz. With a selector switch, the instrument normalizes the power meter reading to compensate for the Calibration Factor of a thermistor mount used for a given measurement. For portable operation, Option 01 instruments have a rechargeable nickel-cadmium battery. As this instrument can be used as a transfer standard for RF power measuring it is still available from Keysight, with a suitable power sensor. For that purpose a DVM is connected to BNC terminals at the rear side. There is also an HP432B with a digital readout. As you can see the cable between sensor and meter is rather big and sturdy, for a reason. The heads are quite delicate and so are the related voltages coming from the heads to the “bridge” inside the meter. The connector pins are gold plated. Don't drop the sensor. For stability reasons, in daily practice, the HP432 is preferred over the HP431.