The First Alert CO615 Dual-Power Carbon Monoxide Plug-In Alarm you to chanceful carbon monoxide. This carbon monoxide detector a backlit digital display that shows at a glance the carbon monoxide level in the room, as well as the unit 's power level. The dual-power design with battery backup this private carbon monoxide detector can monitor even in the event of a power outage. It into any 120-volt outlet and features an end-of-life timer that lets you know when the monitor needs to be replaced. A lone silence and test button confusion and allows you to silence and test the alarm easily.