Features: brand new and high quality There are 9 types you can choose, brown 3 in 1, brown 4 in 1, brown 5 in 1 , orange 3 in , orange 4 in 1 , orange 5 in 1 , white 3 in 1 , white 4 in 1 and white 5 in 1, among them, 5 in 1 type can connect with for smart phones. Real-time monitoring and real-time display of carbon dioxide concentration per cubic meter. It can detect and display the temperature and humidity of the environment to help the user understand the environment. It is suitable for office, home, gym and other occasions, with a wide range of applications. Intelligent color screen display, clear numbers, easy to identify and read. In alert mode, the user is alerted to the environment by changing the color. It has a long life and can be recharged using a USB cable. Small and portable, easy to carry, does not take up too much space, can be installed in the home. Specifications: Material: ABS Size: 140x102x52mm/ 5.51x4.01x2.04 in Concentration Unit: PPM Measuring accuracy: 10ppm Measuring range: 400-5000 Operating voltage: 3.7V Current: 120 ma Power: 0.4 for W Battery: 3.7V, 1400mAh Package Includes: 1x CO2 Detector 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.