1. 1.3in1 function: CO2 concentration detection, thermometer and hygrometer in a single device. 2. Battery powered: built in 1500mAh lithium battery; charges via USB charging cable. 3. Color screen and ring indicator: displays the current CO2 data, temperature and humidity data; the colored ring changes according to the CO2 content. 4. Easy to operate: long press the on off key for 3 seconds to turn the device on or off; it will detect CO2 automatically. 5. Real time readings: clear, straightforward display of CO2, temperature and humidity for quick at a glance monitoring. 6. Use scenarios: In a home or apartment to monitor air quality after cooking or during ventilation In an office or conference room to ensure adequate fresh air during meetings In a classroom, laboratory or workshop to track environmental conditions during activities 7. Why this matters: provides essential three in one functionality in a single unit, with a long lasting battery and USB charging, automatic CO2 detection, and an at a glance color ring that helps you assess air quality quickly without complex setup.