The testo 6621 temperature and humidity transmitter offers you accurate measurement of temperature and humidity values in rooms or in ducts. As a transmitter, it converts the measured parameter into a standardized electrical signal and is therefore able to be used in automated building services. The testo 6621 temperature and humidity transmitter offers these advantages 2 analog outputs (temperature/humidity), 1 passive humidity and temperature analog output as an option Patented humidity sensors: The Testo humidity sensor is high-precision and has long-term stability Adjustment without disassembling the temperature and humidity transmitter P2A software for parametrization, adjustment and analysis saves time and money during commissioning Optimum calibration concept through adjustment of the whole signal chain (1-point, 2-point and analog adjustment) 2-line LC display optional Product versions: The temperature and humidity transmitter is available in various designs – for measurement in rooms or in ducts