About This 【HIGH ACCURACY】CO2 Accuracy: 0~2000ppm(±50ppm or ±5% of the reading); 2000~9999ppm(±10% of the reading) 【LARGE MEASURING RANGE】CO2: 0~9999ppm ; Temperature: -10~60°C(Accuracy ±0.6°C) ; Humidity: 0.1% ~ 99.9%RH(Accuracy ±3%RH) ; Dew Point: -20.0~59.9°C ; Wet Bulb: -5.0~59.9°C 【USER-FRIENDLY】Portable Handle Design, Easily manual calibration on CO2 and humidity, Stable NDIR CO2 sensor 【 POWER SUPPLY】Dual power source: battery (included) or 9V adaptor (**NOTED: adaptor is not included in set). Power from battery is automatically cut off when 9V adaptor is in use 【APPLICATION】IAQ monitoring and survey, especially on CO2 level and air ventilation become widely applied in public areas such as offices, classrooms, factories, hospitals, and hotels. Overview Brand : Gain Express Style : Digital Power Source : Battery Powered Item Weight : 200 Grams Alarm : Audible Operating Humidity : 99 9 percent Upper Temperature Rating : 60 Degrees Celsius Sensor Type : Non Dispersive Infrared Unit Count : 1.0 Count Manufacturer : Gain Express Holdings Ltd.