1.9 in 1: Multifunctional air detector that measures CO2 concentration, CO concentration, TVOC value, HCHO value, PM2.5/PM10 value, temperature and relative humidity. Sensor technology Uses an air semiconductor PM2.5 sensor and an electrochemical performance chip for improved accuracy. Detection accuracy can reach up to 1 PPM. Usage and operation Suitable for office, school, warehouse, and agricultural plantings. No calibration required at startup; automatic operation. Display and alerts Large digital screen with backlight for clear readability. Alarm function to alert you when readings exceed set thresholds. Key benefits Realtime, multiparameter air quality data in a single device, enabling quicker and more informed decisions about indoor environments. precision measurements with a dedicated PM2.5 sensing and electrochemical chip combination. Easy setup with automatic operation and a readable backlit display for any lighting condition. Builtin alarm helps you respond promptly to unhealthy air levels. 23 practical use scenarios Office or meeting room: Monitor CO2 concentration, temperature and relative humidity to optimize occupancy levels and comfort, while tracking CO and VOCs to maintain healthy air quality. Classroom or school environment: Keep track of CO2, TVOC, PM2.5/PM10, and HCHO to ensure a safe learning space for students and staff; use the alarm to prompt ventilation when needed. Warehouse or agricultural planting facility: Continuously monitor PM2.5/PM10, CO2, CO, TVOC, and HCHO to protect workers and crop conditions, with automatic readings displayed on the backlit screen for easy supervision.