Collection: Indoor Air Quality (IAQ) and Combo Sensors

Indoor Air Quality (IAQ) directly impacts occupant health and productivity in commercial buildings. Poor ventilation and pollutants such as mold, VOCs, CO₂, and particulate matter can cause headaches, fatigue, and reduced performance — while well-managed air quality improves comfort and well-being. IAQ and combo sensors monitor these conditions and signal HVAC systems to automatically adjust for cleaner air. Combo sensors measure multiple parameters in a single device, with many models combining temperature and relative humidity, and others adding CO₂, CO, NO₂, or particulate matter monitoring. We carry IAQ and combo sensors from Senva, Gentex, Siemens, Greystone, and other trusted manufacturers.

Greystone HTRC3NI Room Humidity/ Temperature Transmitter, 3%, Concealed LCD, 4-20 mA output

Greystone HTRC3NI Room Humidity/ Temperature Transmitter, 3%, Concealed LCD, 4-20 mA output

Regular price $236.04 USD

Regular price Sale price $236.04 USD
Greystone HTRC3LVS Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Greystone HTRC3LVS Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Regular price $267.52 USD

Regular price Sale price $267.52 USD
Greystone HTRC3LV Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Greystone HTRC3LV Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Regular price $262.20 USD

Regular price Sale price $262.20 USD
Greystone HTRC3LIS Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 4-20 mA output, Override switch (Includes OCC input)

Greystone HTRC3LIS Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 4-20 mA output, Override switch (Includes OCC input)

Regular price $267.52 USD

Regular price Sale price $267.52 USD
Greystone HTRC3LI Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 4-20 mA output

Greystone HTRC3LI Room Humidity/ Temperature Transmitter, 3%, Viewable LCD, 4-20 mA output

Regular price $262.20 USD

Regular price Sale price $262.20 USD
Greystone HTRC2NVS Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Greystone HTRC2NVS Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Regular price $267.52 USD

Regular price Sale price $267.52 USD
Greystone HTRC2NV Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Greystone HTRC2NV Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Regular price $262.20 USD

Regular price Sale price $262.20 USD
Greystone HTRC2NIS Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 4-20 mA output, Override switch (Includes OCC input)

Greystone HTRC2NIS Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 4-20 mA output, Override switch (Includes OCC input)

Regular price $267.52 USD

Regular price Sale price $267.52 USD
Greystone HTRC2NI Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 4-20 mA output

Greystone HTRC2NI Room Humidity/ Temperature Transmitter, 2%, Concealed LCD, 4-20 mA output

Regular price $262.20 USD

Regular price Sale price $262.20 USD
Greystone HTRC2LVS Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Greystone HTRC2LVS Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable, Override switch (Includes OCC input)

Regular price $293.67 USD

Regular price Sale price $293.67 USD
Greystone HTRC2LV Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Greystone HTRC2LV Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 0-5 Vdc or 0-10 Vdc output - Menu-selectable

Regular price $288.44 USD

Regular price Sale price $288.44 USD
Greystone HTRC2LIS Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 4-20 mA output, Override switch (Includes OCC input)

Greystone HTRC2LIS Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 4-20 mA output, Override switch (Includes OCC input)

Regular price $293.67 USD

Regular price Sale price $293.67 USD
Greystone HTRC2LI Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 4-20 mA output

Greystone HTRC2LI Room Humidity/ Temperature Transmitter, 2%, Viewable LCD, 4-20 mA output

Regular price $288.44 USD

Regular price Sale price $288.44 USD
Greystone CD2RMCVXXXXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, No temperature sensor, No relay, No override, No setpoint

Greystone CD2RMCVXXXXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, No temperature sensor, No relay, No override, No setpoint

Regular price $318.97 USD

Regular price Sale price $318.97 USD
Greystone CD2RMCVXXRXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, No temperature sensor, Adjustable relay, No override, No setpoint

Greystone CD2RMCVXXRXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, No temperature sensor, Adjustable relay, No override, No setpoint

Regular price $334.30 USD

Regular price Sale price $334.30 USD
Greystone CD2RMCV24XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV24XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $327.38 USD

Regular price Sale price $327.38 USD
Greystone CD2RMCV24XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV24XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV24XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV24XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV24RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Greystone CD2RMCV24RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 2, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Regular price $342.72 USD

Regular price Sale price $342.72 USD
Greystone CD2RMCV20XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV20XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $327.38 USD

Regular price Sale price $327.38 USD
Greystone CD2RMCV20XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV20XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV20XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV20XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV20RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Greystone CD2RMCV20RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 20,000 Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Regular price $342.72 USD

Regular price Sale price $342.72 USD
Greystone CD2RMCV14XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, No override, No setpoint

Greystone CD2RMCV14XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, No override, No setpoint

Regular price $331.68 USD

Regular price Sale price $331.68 USD
Greystone CD2RMCV14XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV14XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, No override, 0 - 10,000 ohms

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV14XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, Override switch, No setpoint

Greystone CD2RMCV14XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, No relay, Override switch, No setpoint

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV14RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, Adjustable relay, No override, No setpoint

Greystone CD2RMCV14RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C c/w 11K shunt resistor, Adjustable relay, No override, No setpoint

Regular price $347.01 USD

Regular price Sale price $347.01 USD
Greystone CD2RMCV13XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, No override, No setpoint

Greystone CD2RMCV13XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, No override, No setpoint

Regular price $331.68 USD

Regular price Sale price $331.68 USD
Greystone CD2RMCV13XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV13XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, No override, 0 - 10,000 ohms

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV13XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, Override switch, No setpoint

Greystone CD2RMCV13XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, No relay, Override switch, No setpoint

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV13RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, Adjustable relay, No override, No setpoint

Greystone CD2RMCV13RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Nickel, Class B, DIN 43760, Adjustable relay, No override, No setpoint

Regular price $347.01 USD

Regular price Sale price $347.01 USD
Greystone CD2RMCV12XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, No override, No setpoint

Greystone CD2RMCV12XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, No override, No setpoint

Regular price $331.68 USD

Regular price Sale price $331.68 USD
Greystone CD2RMCV12XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV12XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, No override, 0 - 10,000 ohms

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV12XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, Override switch, No setpoint

Greystone CD2RMCV12XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, No relay, Override switch, No setpoint

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV12RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, Adjustable relay, No override, No setpoint

Greystone CD2RMCV12RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1000 Ohm Platinum, IEC 751, 385 Alpha, thin film, Adjustable relay, No override, No setpoint

Regular price $347.01 USD

Regular price Sale price $347.01 USD
Greystone CD2RMCV08XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV08XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $331.68 USD

Regular price Sale price $331.68 USD
Greystone CD2RMCV08XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV08XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV08XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV08XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $336.74 USD

Regular price Sale price $336.74 USD
Greystone CD2RMCV08RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Greystone CD2RMCV08RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 2.252K Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Regular price $347.01 USD

Regular price Sale price $347.01 USD
Greystone CD2RMCV07XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV07XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $327.38 USD

Regular price Sale price $327.38 USD
Greystone CD2RMCV07XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV07XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV07XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV07XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV07RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Greystone CD2RMCV07RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 10,000 Ohm, type 3, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Regular price $342.72 USD

Regular price Sale price $342.72 USD
Greystone CD2RMCV06XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV06XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $327.38 USD

Regular price Sale price $327.38 USD
Greystone CD2RMCV06XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV06XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV06XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV06XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV06RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Greystone CD2RMCV06RXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 3000 Ohm, NTC Thermistor, ±0.2 C, Adjustable relay, No override, No setpoint

Regular price $342.72 USD

Regular price Sale price $342.72 USD
Greystone CD2RMCV05XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Greystone CD2RMCV05XXXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, No setpoint

Regular price $327.38 USD

Regular price Sale price $327.38 USD
Greystone CD2RMCV05XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Greystone CD2RMCV05XXP00 Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, No override, 0 - 10,000 ohms

Regular price $332.51 USD

Regular price Sale price $332.51 USD
Greystone CD2RMCV05XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Greystone CD2RMCV05XSXXX Room CO2 Sensor, 0-2,000 ppm, Viewable LCD, 1801 Ohm, NTC Thermistor, ±0.2 C, No relay, Override switch, No setpoint

Regular price $332.51 USD

Regular price Sale price $332.51 USD

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Collection: Indoor Air Quality (IAQ) and Combo Sensors

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