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Promote greater household safety with the First Alert 9120BFF Hardwired Smoke Alarm with Battery Backup. This 120 volt AC smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast flaming fires and alerts you with a loud 85 decibel alarm. Designed to be wired directly into your home's electrical system, this hardwired smoke detector features a backup battery that helps keep the alarm functioning even in the event of a power outage. The gasket less mount helps ensure a perfect alignment for easy installation, while tamper resistant locking pins keep the alarm secure. And thanks to the convenient test/silence button, you can easily check whether the alarm is functioning properly and mute false alarms. This smoke alarm can integrate with up to 12 other First Alert or BRK hardwired alarms and features a latching indicator that identifies which unit triggered the alarm.
Amazon.com
Introducing the revolutionary BRK 9120 series smoke alarms which 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. BRK Electronics smoke alarms are designed to be easy to install, easy to maintain, and quality-engineered for years of virtually maintenance-free service.
The 9120B AC-powered smoke alarm with battery backup includes these features:
- Ionization sensor which helps detect fast flaming fires that consume combustible materials rapidly.
- 120-volt AC inter-connectable (with maximum 18 compatible devices). The alarm can be interconnected with up to 12 other compatible smoke alarms and six compatible devices like bells, horns, repeaters and door closers. If one unit triggers an alarm, all smoke alarms in the series will sound. Power indicators show which unit in the series initiated the alarm.
- Latching alarm indicator which automatically identifies which unit initiated the alarm.
- Smart technology to reduce nuisance alarms.
- 9-volt battery backup for peace of mind during power malfunction.
- Single test/silence button which both silences a non-threatening alarm or low battery warning and allows you to test the unit's functionality.
- Perfect mount system including a gasketless base for easy installation and new mounting bracket that keeps the alarm secure over a wide rotation range to allow for perfect alignment.
- Mounting bracket lock for tamper resistance.
- Dust cover to keep unit clean during construction.
- 10-year limited warranty. All BRK Electronics smoke alarms meet UL 217 standard and are listed with the California State Fire Marshal. They use the new UL mandated repeating 85-decibel alarm horn pattern. 10-year limited warranty. This unit is approved for sale in Oregon after new revisions on law HB2586.--Bree Norlander
What's in the Box
One smoke alarm, one 9-volt battery, and user's manual
Jonathan B.
2025-08-29 11:10:38
I needed to replace a First Alert model 9120B: it started to chirp because the battery was low. When I removed it from the ceiling I saw that it was over ten years old. I read that smoke detectors should be replaced at that age. I wanted an identical replacement so it would fit on the same mounting bracket in my ceiling and use the same power connector that's connected to AC power in the ceiling.I saw this model, 9120BFF, and the photos on the Amazon page show the unit labelled 9120B despite the "FF" at the end of the model number in the product description. I wasn't sure if it was the same, so I tried searching for model 9120BFF, but all I found was the same page on Amazon.But I ordered it anyway, and it is indeed the First Alert model 9120B. It is an exact replacement and works great. It fits on the same mounting bracket and uses the same power connector that my old smoke detector used. It comes with a new mounting bracket and power connector, which I don't need. And it comes with a new 9V battery: there's a plastic tab covering the battery terminals so no power is drawn until you pull the tab out of the unit when you install it.So why is this called model 9120BFF instead of 9120B? I think it's the packaging: see the picture attached. It comes in a plain corrugated box, which I assume is how they sell it to contractors. It's not in consumer packaging with a glossy cover like you'd find in a retail hardware store. But it's the same product: the label on the unit says Model 9120B, and it comes with instructions for that model. There's one other clue that it is sold to contractors: it includes a plastic dust cover that looks like a miniature shower cap. The dust cover is to be used during construction to keep dust out of the unit; you remove it when construction is finished. (It could be that the dust cover is also in the consumer version; I'm just guessing here.)Anyway, I'm happy with the purchase: it didn't require any ceiling work to replace my old smoke detector, which was my goal.
houston
2025-08-20 16:34:48
Work as intended and easy to install will buy again
Scott Hansen
2025-07-29 15:57:53
It took me a long time to decide which smoke detectors to buy for my house, this model or the brand made by Kiddie. My house already had the Kiddie brand and this would mean a much faster replacement for all the smoke detectors in my house. Over time the Kiddie brand tended to chirp a lot and that drove everyone in the house crazy, especially my older and wonderful dog. My daughter said a candle lit in her room also set off all the smoke detectors in our house.If you go to the store you will find these labeled "BRK" with the words "First Alert" in smaller letters underneath and they come in a yellow and black box. It is unfortunate. Yellow and black packaging reminds me of generic food items back in the 70's and these items had a reputation for being below par. If I did not know what I was looking for I would have passed over these units in favor of something else, and I also noticed that BRK and First Alert puts their more expensive models in fancy and beautiful packaging. Thus, I fear that this company intentionally brands this "entry level" smoke detector in yellow and black to dissuade people from buying it and moving up to the more expensive models.I bought the contractor pack of this item as well as three single units to replace the nine smoke detectors in my house. All of these come with a free battery. I knew I would have to take down the old detectors, take down the mounts, and disconnect the old wiring in order that I be able to put in the new mounts and the new wiring for this smoke detector. It is a job that takes about 10 minutes at the most to completely swap out each of the units. Remember to shut off the circuit breaker!The alarm itself looks great. I like the design a lot better than the flat plastic orb. Once the new wiring harness is connected and the mount is secured to the ceiling, the new detectors snap easily into place for the wiring and you twist it onto the mount. The battery compartment is on the side and although the door for the battery looks cheap, all held up well and none broke. The alarm itself is easy to test, push the big button, and the alarm is loud enough to get anyone's attention. So far, cross our fingers, there have been no errant cheeps and no false alarms. Now to give Kiddie credit our old alarms were nearing the end of their expected lifespan so the new ones would have probably worked as well. I admit it, I went for the name brand!
rachelm
2025-06-07 17:49:35
I got a different First Alert smoke detector a few months ago that came with easy-exchange adapter harnesses for rewiring after switching from different brands. This one comes with a harness with no adapter, so you'll need some wire nuts to hook it up yourself. There are many videos online on how to do it. Otherwise everything works as expected!
Houston H. Markley
2025-05-30 18:52:05
excellent replacement for old detectors that no longer work. easy to install and fit the old wiring plug
Carol S
2025-02-06 14:28:33
This is to replace the one I've had for approximately 17 years! It is exactly like the old one so I'm sure it will last a long while.
Mr. Clean
2025-01-31 18:32:32
Have in every room.
Rex Huston
2025-01-15 14:39:30
Because I was replacing another detector from BRK I only needed to plug it into the exsisting jack. I tested it and it coordinates with the other detectors in the house.
Anthony Dubois
2025-01-12 17:52:30
Easy installation. Not near the false alarms as my old one. And easy 1 button push to disable a false alarm.
Phreddy
2024-12-16 18:48:15
Works well
Customer
2024-12-15 14:42:34
Easy to install. Straight-forward instructions. Good price.
BlackeyedSue
2024-12-05 14:11:28
These were easy to install, given that my First Alert smoke detectors had given it up after only one year of use. These were installed to replace the two that died, and they were throw aways ( which I really disliked). These ones have a drawer for a backup battery which is the way to go. Hopefully they perform well. So far so good. But the proof is in the performance
Brian Knott
2024-11-21 13:10:47
Easy to install
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