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Designed to help promote household safety, the First Alert 9120B Hardwired Smoke Alarm with Battery Backup can provide a vital early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires.
Ionization Sensor Reliably Detects Flaming Fires
The First Alert 9120B Hardwired Smoke Alarm with Battery Backup comes equipped with an ultra-reliable ionization sensor to provide the earliest possible warning of a fast-flaming fire. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials.
Gasket-less for Easy Installation
To facilitate hassle-free installation, this smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the alarm secure over a wide rotation range while maintaining perfect alignment. The alarm also comes with a dust cover to keep the unit clean during construction. AC-powered smoke alarms must be installed in accordance with all local electrical codes.
Battery Backup for Detection During a Power Outage
This smoke alarm is designed for hardwired installation, but it also features a battery backup that helps ensure continued functionality in the event of a power outage. The unit comes with a 9-volt battery and features a pivoting, easy-to-access battery drawer that allows you to replace the battery without dismounting the alarm.
Works in Tandem with Other First Alert Alarms
In addition to functioning independently, this smoke alarm can also integrate with up to 12 other First Alert or BRK hardwired alarms for coverage of larger spaces. It also integrates with up to six other compatible devices, such as bells, horns, and repeaters. If one alarm in the series is triggered, they will all sound. The alarm features a latching indicator to identify which unit triggered the alarm, alerting you to the area of danger.
First Alert Smoke Alarm 9120B
Recommended replacement for the following obsolete models:
First Alert SA4120B
First Alert SA4121B
First Alert SA4919B
Average Rating Based on 205 reviews: (5)
9120B - 03/14/2019
Reviewer: Floyd Schmitz
Ordering was very simple and the service was fast. Was able to replace my older First Alert smoke alarms eight in all in about 90 minutes. This included replacing the ceiling brackets. Yes, the new smoke alarms were compatible to the old brackets, but for a cleaner look it was easy to replace the old brackets with the new ones. I was very pleased that the smoke alarms came with the 9-volt batteries.
It connects with all the other ones we have - 03/14/2019
Reviewer: Shawn Long
This was easy to install and connects with all the others we have.
Quick and easy swap out - 03/12/2019
Reviewer: Gerald Lomashewich
Replaced an earlier version of this smoke detector. The new detectors used the same hardwire connection as the old one. Just had to replace the base on the junction box and put on the new smoke head. Easy! and my house is up to date for another 10 years. Great service and shipping from the First Alert online store. If you need First Alert products, just go to the online store. They will have what you want.
No Problems - 03/11/2019
Reviewer: Brian Hernandez
No issues. I tried calling on the weekend, but Sales Desk apparently is only open on weekdays. I called the service number and, since the smoke detector that I was replacing was over ten years old, the service desk helped me to ID the proper replacement model. I then went and ordered it online. Product arrived less than a week later. All good.
Perfect Match - 03/11/2019
Reviewer: Mark Messina
The smoke detectors that I needed to replace were old, this unit was the exact fit and the plug for the wiring was the exact match. Very easy to install!
Perfect, Quick Service, Right Price - 03/05/2019
Reviewer: Milton Karl
Everything you want, Great price and service
Reviewer: Justin Sabelman
Fast to ship! Good Product!
Thanks! - 03/04/2019
Reviewer: Joe DeChristopher
Good Customer Service. Fast and free ship! It's ALL good.
Very good product - 03/01/2019
Reviewer: Robert Bujakowski
Very good product
Smoke - 03/01/2019
Reviewer: YILI Pan
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