The First Alert CO605 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. Keep your family safe with this easy to use plug in carbon monoxide alarm; It works with any standard outlet and also has a battery backup for continuous monitoring of Carbon Monoxide levels, even if there's a power failure Features an advanced electrochemical carbon monoxide sensor that accurately detects carbon monoxide levels, no matter where the detector is placed in the room Simple to use, with a single test/silence button; a loud 85 decibel alarm sounds when Carbon Monoxide levels reach dangerous levels. Low battery signal mute, quiets low battery signal for upto 8 hours To ensure complete protection make sure to place one on each level of your home and in each bedroom 7 year limited warranty; Equipped with end of life signal chirp, so you know when its time to replace the unit for safety All first alert CO alarms are rigorously tested to meet UL standards. Item length is 3.4 inches , item width is 1.38 inches and item height is 5 inches Loud 85-decibel alarm sounds when CO levels are elevated