Maintenance-free and saves money???never replace batteries for the life of the alarmSave headaches by eliminating annoying low battery chirps10 year sealed batteries provide continuous protection???even in the event of a power outagePermanent Power batteries feature the revolutionary Duracell Duralock Power Preserve TechnologyLithium-free 10 Year Sealed battery alarms???safer and greener + no hazmat handling requiredPatented microprocessor intelligence virtually eliminates nuisance alarmsIdeal for installation in EVERY roomPerfect for new or replacement installationsETL listed to UL Standard 2034 and California State Fire Marshal approved10 Year Limited Warranty on battery and alarm