Features: Mini Air Quality Monitor: Can measure CO2, temperature(/) and humidity at the same time, very suitable for home and office. With backside hole, you can hang the air quality monitor on the wall. High Accuracy Sensor: Adopts infrared sensor to measure CO2, temperature and humidity, which is more accurate, more reliable and more durable than traditional electrochemical sensors. Automatic Alarm System: When the CO2 value exceeds 1500PPM, an alarm will be issued automatically, you will hear beep sound, which notify you to keep the indoor environment ventilated in time. Large Screen Display: Clear and easy to view, and designed with colorful indicator light to show CO2 levels(1-700PPM green, 70-1500PPM yellow, 1500-5000PPM red), suitable for using in bedroom, office, school, car, etc. Built-in Rechargeable Battery: Built-in 2400mAh large capacity lithium battery that can be recharged by provided USB charging cable, long working time and quick charging. Specifications: Color: Black Sensor: Infrared Sensor Detection CO2: 400-5000ppm Detection Temperature: -10 to 40/ 14 to 104 Humidity Range: 0%-99% RH Power supply: Built-in 2400mAh Lithium Battery Charging: 5V 1A USB Item Size: 9.8 * 9 * 4cm/ 3.9 * 3.5 * 1.6in Packing List: 1 * Air Quality Monitor 1 * USB Charging Cable 1 * Users Manual(English & Chinese)