Kidde KNCOBLCBA Carbon Monoxide Alarm The Kidde ACDC Carbon Monoxide Alarm plugs directly into your home's standard wall outlet making installation quick and easy. The 9 volt battery backup provides protection even during power outages when many CO incidences occur. The tamper resistant feature deters tampering or theft of the unit. The Kidde alarm uses advanced electromechanical sensing technology to monitor for carbon monoxide levels in your home. This alarm has a clean low profile design.