Kidde Worry-Free, 10 Year, Sealed Battery, Carbon Monoxide Alarm, Uses Electro-Chemical Sensing Technology To Protect Families, No Battery Replacement Required Over The 10 Year Life Of The Alarm, Alarm Automatically Activates When AttachedTo The Mounting Bracket, Tests/Reset Button, Green LED Light Indicates Alarm Is Operating Properly, Red LED Light Indicates Dangerous Levels & Alarm Will Sound End Of Life Warning, UL Listed, 10 Year Warranty, Clam Shell.