Features:  3-in-1 Multifunction: This portable air quality monitor detects CO2 concentration, temperature and humidity in real time, it cares for your health and can be widely used in home, office, car, classroom, library, hotel, gym, greenhouse, warehouse and more indoor places.  LCD Backlight Screen: Displays CO2 (current/ maximum/ minimum), temperature (ambient/ dew point/ wet bulb), humidity, date, time, battery level and etc.. LCD digital screen with backlight for easy and clear reading even in dark environments.  3-color Indicator & Alarm Buzzer: Set the low and high alarm value (400-4000PPM limited range); white backlight means normal, green backlight flashes and the buzzer emits intermittent sound when the CO2 value is between low and high alarm values, red backlight flashes and the buzzer emits continuous sound when the CO2 value exceeds high alarm value.  Data Logging & USB Connection: 5-60s adjustable interval, up to 26 days of continuous recording under the setting of 5s interval. Connect the tester to computer; find the removable disk to view the data clearly.  Removable & Rechargeable Battery: Built-in 750mAh li-ion battery, it can last for about 4 hours when fully charged. Easily open battery cover to replace or remove battery. With USB cable for quick charging via power adapter, power bank, laptop, etc.  Accurate Detection & Concise Appearance: Adopts sensitive sensor and air convection detection, quick and accurate detection. Simple but stylish appearance, desktop or wall mounted installation, fits in well with different decorating styles. Compact and lightweight, easy to carry.    Note:  1. Please read the user manual carefully before use.  2. Size and color may be slightly different due to manual measurement and different light conditions. Thanks for understanding.    Specifications:  Color: White  Material: ABS  Screen: Digital LCD, with Backlight  CO2 Detection Range: 400-5000PPM; Resolution 1PPM; Accuracy ±(50PPM+5% of reading)  Temperature Measurement Range: -10~50℃; Resolution 0.1℃; Accuracy ±1.5℃  Humidity Measurement Range: 1~99% RH; Resolution 1%; Accuracy ±4%  Time Display: Year-Month-Day-Hour-Minute  Temperature: Ambient/ Dew Point/ Wet Bulb  CO2 Unit: PPM/ % Switchable  Temperature Unit: ℃/ ℉ Switchable  Data Storage: 5s interval, 26 days of continuous recording  Charging Port: Micro-USB, DC 5V  Removable Battery: 3.7V 750mAh Li-ion Battery  Work Temperature: -10~50℃  Storage Temperature: -20~70℃  Item Size: 125 * 83 * 38mm / 4.92 * 3.27 * 1.50in  Item Weight: 224g / 7.90oz  Package Size: 20 * 11 * 6cm / 7.87 * 4.33 * 2.36in  Package Weight: 336g / 11.86oz    Package List:  1 * Air Quality Tester  1 * USB Cable  1 * User Manual (English)