Features: 3 Funtions: this item is used for carbon dioxide concentration detection, thermometer and hygrometer at the same time. Battery supply: installed 1500mAh lithium battery, use USB charging cable to charge it. Color screen: show the current CO2 data, humidity and temperature data. The colored ring will change according to the CO2 content. Easy to operate: touch the "on-off" key for 3 seconds to turn on and off. It will detect the CO2 automatically. Compact and portable: this item is suitable for the kitchen, bedroom, living room, or take it when going out. Package Includes: 1x Gas Monitor with Battery Specifications: Detection Technology: Infraed Detection Technology Display Mode: LED Digital Display+LCD Screen+Backlight Proper Temperature: 1-70c Testing Range: 400-5000ppm Product Specification: 68x70x40mm/2.7x2.8x1.6inches Sensor: Infrared Sensor Operating Voltage: 5V Battery Capacity: 1200HMA, with Power Indicator Product Size: 90x70x35mm/ 3.5x2.8x1.4 inches Charging port: Type-C5V Material: Plastic CO2 Instructions: 0-799ppm: Green Flashing 800-1199ppm: Yellow Flashing 1200-1599ppm: Orange flashing 1600-1999ppm: Red Flashing Four colors Flashed above 1999ppm. note: Please allow 1-3cm error due to manual measurement. pls 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.