Origin:Mainland China Portable CO2 Meter Digital Temperature Humidity Sensor Tester Air Quality Monitor Carbon Dioxide TVOC Formaldehyde HCHO Detector The compact carbon dioxide concentration measuring device can measure carbon dioxide concentration (CO2 concentration), temperature and humidity in real time. CO2 concentration can easily identify dense situations, so you can check when to ventilate properly. Very suitable for use in various places, such as homes, shops, offices, etc. This is an indispensable item for the coming season of with good ventilation. The provinces CO2 concentration is less than 1000 ppm as a standard for good ventilation to avoid the high risk of group This item does not measure the entire space, but is measured around the device. When used in a larger space, the measured value may vary depending on the surrounding environment. 1. Do not use it for purposes other than the intended purpose. 2. Do not place this product where children can reach it. 3. Please use the built-in lithium battery and standard DC-5V charger. 4. Place the magnet near the tape, magnetic card, ticket or clock 5. When placed, the magnetic recording may be damaged or magnetized to prevent use. 6. Please do not cover the intake and exhaust ports to avoid deviations in the values during use. 7. In a dusty environment, the air quality is poor, so please don't use it frequently to extend its life. 8. Avoid incorrect values and prevent internal circuit failures of the equipment. 9. Please do not use it in a place with high temperature and humidity or near a strong magnet. 10. Please use it within the humidity range of 22F-104F (0C-40C). 11. Please store the device and accessories within the temperature range of -4F to 122F (-20C to 55C). 12. Too low or too high ambient temperature will cause malfunction. 13. Please do not use bottles or other sharp objects on the air outlet or charging port to avoid damage. 14. Do not disassemble or modify the product. 15. Do not apply strong vibration or shock. 16. The product is an electrical product, so please do not use it with water or wet hands. 17. Places that become high or humid in blast furnaces or futons (near stoves or hot air heaters). 18. Do not use or store in direct sunlight or in a car under the scorching sun. 19. It may cause malfunction or danger to the display, battery/case/circuit. 20. If the device gets dirty, please wipe it with a dry soft cloth. 21. Wiping with alcohol, thinner, benzene, etc. may cause deformation or discoloration. 22. Do not shorten the terminals. 23. Compact carbon dioxide concentration measuring instrument 24. Real-time monitoring of carbon dioxide concentration, temperature and humidity 25. Visualize the status of carbon dioxide concentration by color and value Contain: 1x carbon dioxide detector Note: The product needs to be equipped with two 18650 batteries (not included)