Center 512 Carbon Dioxide Meter with Datalogging Suitable for checking and monitoring IAQ (Indoor Air Quality) in offices, schools and homes. Product Features• CO2, Humidity And Temperature Sensors• Dual Wavelength NDIR CO2 Sensor (Non-Dispersive Infrared) For Superior Stability• User Operated CO2 Calibration• Data Hold & Max/Min/STEL/TWA Function• Adjustable Auto Power Off Timer• Internal CO2 Alarm Buzzer• Datalogging Up To 32,000 Sets• USB Interface, PC Software Included• Backlight Display Function Specification Measurement Range: CO2: 0 ~ 30000 ppm (5000~30000 ppm over range) Temperature: -20 to 60°C Humidity: 0 ~ 100%RH Accuracy: CO2: ± (75 ppm + 3% of reading) (0 ~ 5000 ppm) Temperature: ± 1.0°C Humidity: ± 4.5%RH Resolution: 1 ppm, 0.1°C, 0.1%RH Response Time: 20 seconds Battery Type: 9V alkaline battery Battery life: Approximately 10 hours normal use (alkaline battery) Operating Condition: 0°C to 50°C(< 90%RH) Storage Condition: -20°C to 60°C(< 75%RH) Dimensions: 226.5x65x38.5 mm Weight: 273 g Accessories: 9V Battery, Instruction Manual, micro USB cable, Software, Case Download Product Sheet PDF