The new Kidde KN-COPP-B-LPM carbon monoxide alarm is the only battery-operated alarm that includes a backlight digital display feature. This key feature adds an advanced level of protection that you have come to expect in a Kidde manufactured product. The battery operated CO alarm includes multiple mounting options, allowing installation on a wall or tabletop. This alarm has been carefully designed and tested to detect CO concentration in a residential environment. It provides continuous monitoring of CO levels, even during power outages when many CO incidents occur. The backlit digital display feature allows for easy viewing of carbon monoxide levels from 30-999 PPM (parts per million). The KN-COPP-B-LPM will also detect and store concentration CO levels as low as 11 and up to 999 PPM with its peak level memory display. This alarm includes a snap-on cover that gives immediate access to the batteries and a safety feature that makes it difficult to close the cover without the batteries being installed. Updates digital reading every 15 seconds, allowing you to see if levels change. The backlit display helps to see the displayed reading in the dark, and the backlight appears during the peak level cycle. The light will also turn on when the peak level button is pressed. The peak level memory displays the highest CO concentration measured since the last reset. The test/reset button tests CO alarm circuit operation and allows you to immediately silence the alarm. A low battery signal alerts users when the batteries need to be replaced. Includes informative LEDs: green LED for normal operation, red LED for alarm. The alarm alerts user to replace CO alarm after 7 years of operation.

物が物ですので、理解できない方は、無闇に使わないほうが良いかと思います。
操作ミスで事故になりますし。(-。－；)


もう一つは