The Kidde KN-COPP-3 AC powered, plug-in carbon monoxide alarm utilizes sophisticated electronic components and unmatched sensor technology to protect you and your family from the dangers of CO. The KN-COPP-3 includes a 9 VDC battery backup that provides continuous monitoring of CO levels, even during power outages, when AC-only units are not providing protection. The KN-COPP-3 will detect and store measured data of concentrated CO levels as low as 11 and up to 999 ppm with its peak level memory display. This alarm gives you several mounting options, including direct-plug, a 6 ft power cord or table top.