Common Display screen Test variables: carbon dioxide (CO2), temperature, humidity Large 2200mAh capacity Lithium battery 5V Micro-USB charging Low battery Specifications: Display : Common Display Screen Pressure: 86Kpa - 106Kpa Sampling time: 1.5 seconds Storage temperature: -10 c to 60 c; CO2 Concentration Unit: PPM Power source: Lithium battery with a capacity of 2000mAh; DC 5V power supply via micro-USB port Instructions: 1. Start When you long press the power button, the air quality monitor will start. 2.About Charge When the low battery is displayed, the device needs to be . Insert the included or another compatible Micro-USB charging cable into the device. Attach the other end to a USB DC charger (such as a smart phone charger) which outputs DC 5V at more than = 1000mA. Charge fully for at least 2-3 hours before use. Avoid charging with a USB computer port which only outputs 500mA. 3. Parameters Carbon Dioxide Monitor Indicators Measuring range: 400-5000PPM Resolution: 1 PPM Measuring range: -10-50 c Technical temperature and humidity indicators Humidity range: 20% -85% RH Measurement accuracy: +/- 1 c Measurement accuracy: +/- 4% rh CO2 sensor: infrared (NDIR) Colour: black Material: ABS Package Contents: 2 x Air Quality Monitor 2 x English manual.