The First Alert CO606 plug in carbon monoxide alarm with battery backup uses an electrochemical carbon monoxide sensor the most accurate technology available. The alarm easily plugs into any standard outlet with no additional mounting. Battery backup ensures alarm Works even during power outages. Mute button silences any nuisance alarms. Single button also tests alarm functions. Carbon monoxide alarm utilizes electrochemical sensor for increased accuracy. 7 year limited. Co alarm meets UL standards. There are no complicated displays or settings to navigate.