Amprobe CO2-100 Handheld Carbon Dioxide Meter Handheld digital meter measures ambient level of carbon dioxide (CO2) to monitor indoor air quality and performance of heating, ventilation, and air-conditioning systems Displays current CO2 levels, long-term average CO2 levels measured over an 8-hour period, and short-term average CO2 levels measured over a 15-minute period Alarm notifies operator when CO2 levels reach or exceed a preset threshold, CO2 measurement up to 9999 ppm Liquid crystal display (LCD) shows ambient CO2 levels, as well as air, wet bulb, or dew point temperature and humidity Manual calibration helps ensure accurate humidity and CO2 readings