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.
Keep your family safe with this hardwired smoke alarm the battery backup means constant monitoring, even if there’s a power failure
Equipped with an ionization sensor, this smoke alarm reliably detects smoke from fast flaming fires and alerts you with an 85 decibel alarm
To ensure complete protection make sure to place one on each level of your home and in each bedroom
Can connect to other compatible BRK or first alert smoke detectors, to ensure all alarms will sound when smoke is detected
Simple to use, with a single test/silence button, and side load battery compartment tamper resistant locking brackets and universal mounting brackets make installation easy
Rigorously tested to meet UL standards120 volt AC power with 9V battery backup to keep alarm functioning during power outage
First Alert has been the most trusted brand in home safety since launching the first residential smoke alarm in 1958 (Based on a First Alert Brand Trust Survey in February 2018)
Faster turnarounds on job sites with the easy-to-install, most-trusted alarms in home safety
13 reviews for BRK First Alert 9120BFF/ SMI100-AC Smoke Detector, Hardwired Alarm with Battery Backup, White, 1-Pack
Add a review
$19.19

Cautious Buyer –
Perfect Replacement and Easy to install
Replacing a 10 year old same brand and model of detector.Perfect fit with hardwired connectors . Easy to install, comes with 9V batteryWorks as expected.Highly Recommended
Craig J. Brunet –
Great smoke detector
The best smoke for your money. Why pay big nox prices when you can get the same model from Amazon cheaper. These smokes are very easy to install. The are reliable and clean looking.
Kindle Customer –
Work as advertised!
They were very easy to install, came with a pigtail so I could wire into my system, work as advertised, and we like how we can look up at night and see the soft green glow knowing that they are ready and working.
Bill –
Smoke Detector replaced easy
I bought this as a replacement for one that was at end of life (Lasted 8 years). Easy to install and works great!I did not notice it was not carbon monoxide detector also. So make sure you check that if you want to monitor both smoke and Carbon Monoxide.Other then that, it fits on the same bracket as my old model SC9120B that is obsolete. Uses the same 120vac connector as the old. Interconnects with the my other 4 original monitors that still work. So if you have one that is NG, (my old one, chirped 3 times every 5 minutes or so even after cleaning and replacing battery) you can just replace that one and be OK.
Magnusm –
Perfect plug and play replacement
Great product. Replaced an original installed 20 year old one hardwired into my house that was malfunctioning. Plugged right into the existing wiring and the existing mounting bracket and no more alerts. Included 9v battery.
Scott Hansen –
Great alarm at a generic price!
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!
HonestUserReview –
Reliable Safety with a Stylish Touch
This is my second smoke and fire alarm from this brand, and once again, it delivers exactly what I hoped for. The sleek design fits perfectly and blends seamlessly with the aesthetics of my home—no bulky eyesore here. Installation was a breeze, taking just a few minutes, and it even comes with a 9V battery included, which is a thoughtful touch. Reliable, stylish, and easy to set up—this alarm checks all the boxes for safety and convenience.
Alan Leichtman –
Smoke detectors
Great replacement great cost and very easy to install.Would and do recommend these
Client d’Amazon –
L’article est tel que décrit. Facile à installer. Je recommande.
Anthony Dubois –
Easy installation. Not near the false alarms as my old one. And easy 1 button push to disable a false alarm.
Garth Kozler –
Works good so far 🙂
Alex G. –
Good detector
Gérald 14 –
Très bon prix.