Check the listing for details. SIEMENS QPM2100 CO2 Duct Sensor, Analog, 24V AC 5WYE9. Condition: New. Listed at 440.52 USD. CO2 Duct Sensor, Air Quality Measurement CO2, CO2 Accuracy +/-50 ppm + 2 Percent of MV, Power Required 24V AC;15 to 35VDC, Output 0 to 10V, 0 to 5V, 4 to 20mA, Display Type None, Housing Material Polyethylene, Housing Color White, Minimum Operating Temperature 32 Degrees F, Maximum Operating Temperature 122 Degrees F, Compatible Building Automation Protocols BACnet IP, BACnet MS/TP, LonWorks, LoRaWAN, Modbus, MP-Bus, For Use With Building Automation Systems Building Automation System Compatible This SIEMENS CO2 duct sensor is for use in air ducts in ventilation and air conditioning systems to help enhance room comfort and to optimize energy consumption by providing demand-controlled ventilation. Model can be used as a control sensor or a transmitter for building automation and control syst.