Indoor Air Quality Meter, Calibration Certificate Type Available Separately, Digital Display Screen Type LCD with Backlight, Features Calculates Time-Weighted Average (TWA) and Short-Term Exposure Limit (STEL), Triple LCD Display, Includes Carrying Case, USB Cable, Maximum Carbon Dioxide Measured 30,000 ppm, Maximum Carbon Monoxide Measured Not Applicable, Maximum Dew Point Measured Not Applicable, Maximum Oxygen Measured Not Applicable, Maximum Pressure Measured Not Applicable