Carbon Monoxide Detector, Calibration Certificate Type Not Certified, Digital Display Screen Type LCD with Backlight, Features Audible Alarm at 35 PPM Increases Beeping until Continuous at 200 PPM, Self Calibration in Fresh Air, Stabilized Electro-Chemical Gas-Specific (CO) Sensor, Includes Carrying Case, Rubber Holster, Maximum Carbon Dioxide Measured Not Applicable, Maximum Carbon Monoxide Measured 1,000 ppm, Maximum Dew Point Measured Not Applicable, Maximum Oxygen Measured Not Applicable