The AQM-101 is designed to measure HCHO concentration, air temperature and relative humidity with visible and audible alarms. This HCHO monitor is an ideal instrument for indoor air quality (IAQ) diagnosis and HVAC system performance verification. Large LCD Displays Hcho Level, Temperature, Relative Humidity, Calendar (Y/M/D) and Time Stable Electrochemical Sensor for Hcho Detection Programmable High Alarm