Portable Indoor Air Quality CO2 Meter - (GSM400)The Triplett Model GSM400 Indoor Air Quality CO2 Meter measures CO2, Temperature, Humidity, Wet Bulb and Dew Point and can be used to measure air quality in office buildings, schools, exhibition halls, shopping malls, meeting rooms, fitness centers, restaurants and other public places. Read More > DESCRIPTION The Triplett Model GSM400 Indoor Air Quality CO2 Meter measures CO2, Temperature, Humidity, Wet Bulb and Dew Point and can be used to measure