Range:CO2: 0 to 2000 or 0 to 5000 ppm (depending on model); Relative humidity: 0 to 100% ; Temperature: 32 to 122°F (0 to 50°C).Accuracy:±40 ppm + 3% of reading (CO2); ±2% (RH).Temperature Dependence:±8 ppm/ °C at 1100 ppm.Non-Linearity:16 ppm.Pressure Dependence:0.13% of reading per mm of Hg.Response Time:2 minutes for 99% step change.Temperature Limits:32 to 122°F (0 to 50°C).Duct Air Velocity Range:0-4000 FPM (20.32 m/s).Humidity Limits:10 to 95% RH (non-condensing).Power Requirements:16 to 35 VDC / 19 to 28 VAC.Power Consumption:Average: 2 watts; Peak: 3.75 watts.Sensor:Single-beam, dual-wavelength NDIR.Output:Current: 4 to 20 mA (max 500 Ω); Voltage: 0 to 5 VDC or 0 to 10 VDC (min 500 Ω); Relay: SPST NO 2A @ 30 VDC; RTD or thermistor per r-t curves (depending on model).Weight:5.6 oz (158.8 g).Enclosure Rating:Duct mount: NEMA 4X (IP66) for housing only; Wall mount: IP20.Agency Approvals:CE.