Carbon Dioxide Detector: Real-time and accurate monitoring of ambient CO2 concentration, humidity and temperature, with date and clock display, and data is updated in real time every 4 seconds. Independent semiconductor sensor: used to measure CO2, temperature and humidity, large color screen, LED digital display, intelligent backlight, soft eye protection, intuitive reading, display more clear, 24-hour real-time monitoring. Long battery life: use 3 AA batteries (need to bring your own) or use USB TYPE-C data cable interface to power, and the battery life can last up to half a month. Automatic alarm system: when the CO2 concentration exceeds 1000ppm, an alarm will be issued to inform you to maintain indoor environment ventilated in time. Lightweight design: small size, easy to carry, and can be used directly by plugging in the USB cable. Can be placed anywhere: schools, offices, bars and restaurants, homes, cars, etc.