Features: 3-in-1: can be used as a detection of concentration of carbon dioxide, thermometer and hygrometer at the same for time. Battery source: 1500mah built-in lithium battery, use the usb charging cable to charge it. Color screen: display current co2 data, temperature and humidity data. The colored ring will change according to the co2 content. Simple to operate: press and hold the "on-off" for key for 3 seconds to switch on and off. It will detect co2 automatically. Mini and portable: can be placed in the kitchen, living room, bedroom, etc. Specifications: Material: ABS Color: black, white Carbon dioxide measurement range: 400-6000 PPM Error: 50ppm 5% Measurement accuracy: 1ppm Color change warning 0-800 green 800-1200 yellow 1200-1800 orange 1800 or more red If it is greater than 1000ppm, an audible alarm will be emitted. Carbon dioxide measurement range: 400-6000 PPM Error: 50ppm 5% Measurement accuracy: 1ppm Note: Please allow 0-1cm error due to manual measurement. Make sure you do not mind before you bid. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 Pcs CO2 detector.