Siemens QFM4160 DUCT RH AND TEMP SENSOR, 2 PERCENT CERTIFIED, RH: 0-10 VDC, T: 0-10 VDCSiemens QFM4160 Duct RH and Temp Sensor, 2 percent certified, RH: 0 10 Vdc, T: 0 10 Vdc This Q Series Duct Relative Humidity Temperature Sensor monitors and transmits changes in humidity and temperature to the building control system. This unit is especially suited for applications where precise, stable humidity sensing is required. It has a 2 percent certified accuracy rating, a 0 to 10 Vdc humidity output signal, and a 0 to 10 Vdc temperature