MODEL 9120B (Old 4120B, Compatible and Interchangeable)AC Powered Smoke Alarm with battery back-up, silence, latching and Perfect Mount system Introducing the Revolutionary 9120 Series smoke alarms. They have been redesigned from the ground up. They install faster, perform better and are even smarter than before. All of these improvements help reduce nuisance alarms and save you time and money. Meets codes where an AC smoke alarm with battery back-up is required.
