The First Alert Hardwired Smoke Alarm with Battery Backup works exceptionally well in detecting flaming fires. Capable of wiring directly into your home's electrical system, these alarms feature a near effortless installation process. This Alarm comes equipped with a Mute Button that serves the dual purpose of quickly silencing your alarm as well as testing its function. First Alert's s 120VAC Hardwired Smoke Alarm also comes equipped with an EZ access battery door that removes the hassle and burden of collecting your alarm from the ceiling and replacing its batteries. The combination of a Battery Backup that provides optimal protection in the event of a power outage and an increased emphasis on the unit's 85d output establish the ultimate in peace of mind. This alarm comes with a 10 year limited warranty and complies with UL217 Standards. Save additionally with the purchase of this bundle. These alarms are also capable of interconnecting with up to 18 other First Alert or BRK hardwired alarms.