Carbon monoxide meter features from 35 PPM to 200 PPM, the beeper sounds periodically, 200 PPM, the beeper sounds continuously. Measure CO quickly and easily in working and living environments. Applications: check dangerous CO levels, identify malfunctioning equipment. Measurement range: 0 to 1000 PPM. Measurement resolution: 1 PPM. Accuracy: 5 percent or +/-10 PPM (0-100 PPM), 10 percent +/- 10 PPM (>100PPM). Warm up period: <2 seconds. Operating temperature: 32 degree F to 122 degree F (0 degree C to 50 degree C). Storage temperature: -22 degree F to 140 degree F (-30 degree to 60 degree C). Operating Humidity: 0-99 percent relative humidity (non-condensing). Battery: 9V (included). Auto power off: after 15 minutes of inactivity. Sensor type: stabilized electrochemical gas-specific (CO). Typical sensor life: 3 years.