Carbon Monoxide Meter, Carbon Monoxide Measurement Range (PPM) 0 to 999, Carbon Dioxide Concentration -, Temp. Range -, Relative Humidity Range -, Dew Point Range -, Wet Bulb Temperature Range -, Oxygen Concentration -, Humidity Accuracy -, Velocity Accuracy -, Accuracy +/-15 Percent, Resolution 1 ppm, Display Backlit LCD, Auto Power Off Yes, Low Battery Indicator Yes, Sensor Life -, Data Hold -, Data Storage -, Power Source (3) AAA Batteries,