Three-in-one monitoring device for carbon dioxide concentration, temperature, and humidity - Three-in-one function: can be used as a carbon dioxide concentration detector, thermometer and hygrometer at the same time. - Battery powered: built-in 1200mAh lithium battery; charging with a Type-C charging cable. - Colour screen: shows current carbon dioxide data, temperature, and humidity. The colour ring changes depending on the carbon dioxide content. - Easy to use: long press the "Switch" button for 3 seconds to turn it on and off. It automatically detects carbon dioxide. Use scenarios - Indoor spaces such as homes and offices to monitor air quality and comfort levels. - Classrooms and meeting rooms to track CO2 during occupancy and improve ventilation decisions. - Greenhouses or plant growing spaces to monitor CO2 alongside temperature and humidity for better growing conditions.