Carbon Monoxide/Carbon Dioxide IAQ Meter with Memory - (GSM350)The Triplett Model GSM350 Carbon Monoxide Carbon Dioxide IAQ Datalogger simultaneously displays CO, CO2, Temperature, and Humidity on its large color display with 4 brightness levels. It can be used to measure air quality in office buildings, schools, exhibition halls, shopping malls, meeting rooms, fitness centers, restaurants and other public places. It has a user settable datalogging duration period of 1 hour, 24 hours, or 7 days with a sampling