First Alert CO606 Plug-In Electrochemical Carbon Monoxide Alarm with Battery Backup features an electrochemical CO sensor to alert you to carbon monoxide. This carbon monoxide detector plugs into any standard electrical socket to monitor CO levels in your home. The simple, user-friendly design features battery backup to allow for continuous monitoring, even in the event of a power outage. In the event of a power failure, backup batteries power the CO detector so it can continue monitoring your space for dangerous levels of carbon monoxide. Uses an electrochemical sensor to alert you to elevated carbon monoxide levels. Designed to alert the soundest of sleepers, a loud 85-decibel alarm warns you when carbon monoxide is detected. Easy to set up - simply plug it into a standard electrical outlet to monitor your space for carbon monoxide. There are no complicated displays or settings to navigate; a single button silences the alarm and tests the CO detector.