**This alarm replaces the 9120B, which has been discontinued*** The BRK SMI100-AC (1046836) is a great choice when it comes to affordable smoke alarms! Interconnect Hardwire Smoke Alarm with Battery Backup – Direct wire-in with replaceable 9V battery backup. Hardwired with battery backup for protection during power outages. – Perfect mount for easy installation. Mounting bracket keeps the alarm secure over a wide rotation range for ideal alignment. – Latching alarm indicator, visually identifies unit that initiated alarm or low battery. – Interconnects with most BRK First Alert hardwired alarms. When one alarm sounds, all compatible alarms sound (up to 12 smoke alarms and 6 other alarms). – Test/Silence Button, temporarily silence or test the alarm with one-touch easy access button. – Precision Detection – Conforms to UL 217 8th Edition Standard