Rohde & Schwarz Thermal Power Sensor NRV-Z55 DC-40GHz, -30 ~ +20 dBm, less than 0.3dB for the whole frequency range, 999 USD;
it is quite strange the sensor no routine calibration procedure, the poor design let me surprice other listing in ebay is so expensive, I just want to say, it is a poor design rubbish kit;
if you want to do the 0.3 dB calibration, I believe the cost is high than my listing price, just keep in your mind, the kit less than 0.3dB then OK.
BTW, if the warranty seal is broken then sell in ebay as part, they are 100% should into dust bin, because, there is no repairable for power sensor if already opened.
ship to US 48 states in free.
https://www.ebay.com/itm/186911654856