3-IN-1: Can function as a carbon dioxide concentration detection, thermometer and hygrometer at the same time. BATTERY POWER SUPPLY: built-in 1200mAh lithium battery, use TYPE-C charging cable to charge it. COLOR SCREEN: the current carbon dioxide data, temperature and humidity. The colored ring will change according to the carbon dioxide content. EASY TO OPERATE: long press the "on-off" key for 3 seconds on and off. The product does not need calibration, startup can be tested COMPACT AND PORTABLE: can take in the kitchen, living room, bedroom, or when going out. Widely used and practical, used for epidemic preventions and control to detect the CO2 concentration in the population, so as to control the number of people and avoids the risk of cross-infection. size: 90 x 70 x 35mm Material:ABS colour:White Package Contents: 3 x Air Quality Analyzer 3 x USB Cable 3 x User Manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.