1The alarm detector includes a catalytic combustion method sensor and an electrochemical carbon monoxide sensor. When a dangerous concentration of carbon monoxide or explosive gas is detected, it will immediately sound an alarm, allowing you to quickly make a judgment and protect your family from injuries. 2The operation is simple and easy to use. Push the test button, connect to the power supply 90V240V or 9V rechargeable battery (not included), the detector will display a 3minute count. 3The display clearly shows the gas level (from 0 to 3000 ppm) that the device has detected and stored, and is updated every 9 seconds to indicate any sudden changes, achieving a good warning effect. 4When the concentration of carbon monoxide reaches 100PPM or the concentration of combustible gas reaches 6%, the LCD screen starts to display the concentration value, the red LED indicator flashes and a loud voice alarm mode is issued. 5It can be easily installed on any wall or ceiling without an electrician, strong applicability and high safety, suitable for offices, bedrooms, living rooms, basements, garages, etc.