This miniature transmitter measures humidity from 0 to 100% and temperature from -40 to +60 degC. It uses little power, and you can remove its sensor to simplify calibration.
This has a rugged aluminium body and interchangeable connector. You can replace the sensor as an alternative to recalibrating the complete instrument and the probe cable has a screw-on quick connector for ease of installation. The sensor has an analog voltage output.
NIWA uses the HMP60 at some air quality sites.