Features: Large-screen digital and character display, instant value and maximum value display. Safety indication: regular light flashing and voice indication. When carbon monoxide concentration Increases, buzzing voice frequency would also be increased. Low maintenance cost. Support carbon monoxide detection. Solid shell and robust electric characters. Carbon monoxide concentration of 0-1000ppm can be displayed on the large LCD screen. Bright back-light lightening; it can clearly indicate carbon monoxide detector under dark environment. Automatically shut off if it is not operated for 10 minutes, to extend battery service life. Convenient to replace battery. Special sensor for stable electronic chemistry carbon monoxide. Sensor of over three-year service life and battery of 100-hour alkaline service life (typical value). Specification: Gas Tested: CO In The Air Measuring Range: 0-1000ppm Resolution: 1ppm Minimum Reading: 1ppm Basic Error: +/-5%(f.s),+/-10ppm Response Time: 60 Seconds Sensor Type: Electrochemical CO Sensor Environment Temperature Test Range: 0~50 32-122,10-90%RH Storage Environment: -10~80; -14~176; 10-75%RH Power: 2x1.5V AAA Batteries (NOT INCLUDED) Size:13.5*5.5*2.8cm/5.3*2.2*1.1in Weight: Approx.158g/5.6oz Package list: 1 x Carbon Monoxide Meter (battery not included) 1 x manual 1Large-screen digital and character display, instant value and maximum value display. 2 Safety indication: regular light flashing and voice indication. When carbon monoxide concentration Increases, buzzing voice frequency would also be increased. 3 Support carbon monoxide detection. 4 Solid shell and robust electric characters. 5 Carbon monoxide concentration of 0-1000ppm can be displayed on the large LCD screen.