Indoor Air Quality Meter, Calibration Certificate Type Not Certified, Digital Display Screen Type LCD with Backlight, Features Non-Dispersive Infrared Sensor (NDIR), Includes Power Adapter, Maximum Carbon Dioxide Measured 9,999 ppm, Maximum Carbon Monoxide Measured 9,999 ppm, Maximum Dew Point Measured 140 Degrees F, Maximum Oxygen Measured Not Applicable, Maximum Pressure Measured Not Applicable, Maximum Relative Humidity Measured 99 Percent, Maximum Temperature Measured 140 Degrees F