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First Alert

First Alert BRK 3120B Hardwired Photoelectric and Ionization Smoke Alarm with Battery Backup, Dual Sensing Smoke Alarm, 1-Pack

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Availability: Only 10 left in stock, order soon!
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Arrives Monday, Jun 23
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Style: Standard Detection


Size: 1-Pack


Configuration: 10-Year Battery


Features

  • The front cover design of the alarm may vary but product function remains the same.
  • The First Alert Hardwired Dual Sensor Photoelectric and Ionization Smoke Alarm with Battery Backup is designed to help provide peace of mind.
  • This dual sensor, photoelectric and ionization alarm alerts you to both smoldering and fast-flaming fires in the event of a home fire emergency.
  • Hardwire alarm includes battery backup for protection during power outages.
  • Two latching features help indicate a low battery or the originating alarm in a system.
  • A single test button makes alarm easy to test regularly.

Description

The First Alert Model No. 3120B is a wire in, 120V AC 60Hz single and/or multiple station photoelectric and ionization dual sensor smoke alarm specifically designed for residential and institutional applications including sleeping rooms of hospitals, hotels, motels, dormitories and other multifamily dwellings as defined in standard NFPA 101. Model 3120B complies with UL217, CSFM, NFPA 72, HUD, FHA and other agencies that model their codes after the above agencies. It meets building codes where AC/DC photoelectric and ionization combination smoke alarms are required. The BRK 3120B is a state of the art hardwired with battery backup smoke alarm that features dual photoelectric and ionization smoke sensing technologies. This alarm features two latching features and two silence features. Alarm Latch: Easily identifies initiating alarm even after alarm condition has subsided. Low Battery Latch: Identifies which unit is in low battery condition by blinking the green power light. Low Battery Silence: Temporarily silence the low battery chirp for up to eight hours. Alarm Silence: Silence alarm for several minutes. Other features include an85dB horn, single button test/silence, an easy access battery drawer and dust cover. OptiPath 360 Technology: Exclusive patented technology provides 360 degrees of direct access to the smoke sensor. Two locking features are provided to prevent battery theft and/or theft of the unit. Connection to AC power is made with a Quick Connect wiring harness. Installation is quick, easy and cost effective.

Brand: First Alert


Style: Standard Detection


Power Source: Battery Powered


Color: Dual Sensing Smoke Alarm


Product Dimensions: 2"D x 5.25"W x 5"H


Item Weight: 11.68 ounces


Alarm: Audible


Compatible Devices: photoelectric


Upper Temperature Rating: 38 Degrees Celsius


Sensor Type: Photoelectric


Brand: ‎First Alert


Style: ‎Standard Detection


Power Source: ‎Battery Powered


Color: ‎Dual Sensing Smoke Alarm


Product Dimensions: ‎2"D x 5.25"W x 5"H


Item Weight: ‎11.68 ounces


Alarm: ‎Audible


Compatible Devices: ‎photoelectric


Upper Temperature Rating: ‎38 Degrees Celsius


Sensor Type: ‎Photoelectric


Global Trade Identification Number: ‎34


Number of Items: ‎1


Manufacturer: ‎First Alert


UPC: ‎029054015334


Part Number: ‎3120FF


Item Weight: ‎11.7 ounces


Item model number: ‎3120FF


Batteries: ‎2 AA batteries required. (included)


Is Discontinued By Manufacturer: ‎No


Size: ‎1-Pack


Pattern: ‎1st Generation


Item Package Quantity: ‎1


Included Components: ‎Smoke Detector, batteries, mount, user's manual


Batteries Included?: ‎Yes


Batteries Required?: ‎Yes


Battery Cell Type: ‎Alkaline


Warranty Description: ‎10 Year Limited


Date First Available: October 3, 2014


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Monday, Jun 23

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • easily replaced my old alarm.
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
Easily replaced my old alarm with this one. If fit on my old base. I like that the batteries are replaceable and that it comes with a little cover for when you are vacuuming or painting to keep the sensor clean. My old alarm had a sealed battery that was supposed to last 10 years. But, after 5 years it was finished. I likely got something like dust on the sensor when cleaning the house. So, I will be more careful to cover this one when working around it. ... show more
Reviewed in the United States on June 7, 2025 by Shelby
    • Good technology and very easy installation.
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
I recently learned that the service life of smoke detectors is about 10 years. Checking my Amazon order history, I found out ours were 12 years old. This is exactly the same model, and it took me less than an hour to put batteries in 6 of these and swap out the old ones. These are dual function (detects smoky fires via photocell, detects hot fires by ionization.) Because they are the same model, they plugged right into the existing ceiling mounts. They are also dual powered, normally by house AC, but with battery backup. I feel well protected for the next 10 years, and have made a calendar note for annual battery changes. ... show more
Reviewed in the United States on May 19, 2025 by Mike Utt
    • The best available with dual-technology, but could be better
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
Pros: • Dual sensing technologies of both ionization and photoelectric • Relatively easy to install • Comes with Duracell Alkaline batteries (that I didn’t use) • Last set was in service 11 years, replaced with the same • Has status LED • Supports AC power with battery backup with multiple alarm interconnect • Has latching status LED • Can clear latching LED, silence alarm, and test with the single button Cons: • Status LED can only be seen from narrow angle • Battery door can be difficult to open, especially up on a ladder • Came with Duracell batteries (read below) • Single test button needs to be pressed hard and held to operate • Have to get up on a ladder to access test button • Narrow viewing angle of status LED makes some impossible to see from below I had installed 3 of these same First Alert (now BRK First Alert) 3120B smoke alarms in 2013. They replaced the original builder installed ionization only smoke alarms that were well past 10 years old. These were all AC line powered, and have the 3 alarms interconnected. At that time, I had to replace the mounting ring, and install new pigtails to match the First Alert connector (why can’t these be standardized?). I selected these alarms because of the dual sensing technologies to detect both smoldering and flaming fires. Since 2013 these alarms when the first set were installed, they mostly functioned properly. If something was smoking in the kitchen the one closest to the kitchen would trigger and the rest would also alarm. If there were false alarms as reviews have commented about, they were so few over 11 years that I don’t even recall them. No, I did not get up on a ladder and clean them weekly. I think in 11 years I cleaned them once when I painted around them. Fast forward to last week when 1 of the 3 alarms started having a low battery chirp. It had been a few years since I last changed the batteries (they had been changed every few years), so not a huge issue – or so I thought. While it was inconvenient at around 11 PM, at least it wasn’t at 3 AM. Well, it turns out the Duracell AA batteries I had installed were both leaking horribly. I did get the batteries out, and cleaned the gunk off the contacts as best as I could do while up on the ladder and installed a pair of Lithium AA batteries. I was concerned how corroded the contacts were, and I knew they had been in service for over 10 years so I figured I would order replacements and didn’t worry too much about the contacts. I even just left the ladder out planning to replace all of them. The next day I started hearing low battery chirps again. Initially I thought it was a bad connection due to contact corrosion. Nope. It was another smoke alarm. Same thing, the Duracell AA batteries leaked. I had already ordered 3 replacements from Amazon, but they didn’t arrive yet. So, I installed Lithium AA cells in this one too. When I went to look on Amazon for 3 replacement smoke alarms I didn’t anything better that was at least dual-technology. I would have liked CO sensing too, but that isn’t a major concern as we have all electric appliances. These still seemed to be the best option for an AC powered wired alarm with interconnected alarm support and backup battery. Plus, it should simplify installation by using the existing pigtail and mounting. When the 3 new smoke alarms arrived, I started replacing all 3 existing alarms. The new alarms look mostly the same as the older ones. The label is a bit different, not necessarily in a good way either. The font size for terminal identification shrunk from a big easily read text to tiny thin print. Sure, the pigtail wires are color coded, but why the tiny font? The existing pigtails were the same so I was able to reuse them. The mounting rings were also the same, so I also reused the mounting rings. This made installation about as easy as it can get. When I went to install the third smoke alarm, it too had leaking Duracell AA batteries. They hadn’t failed to the point of a low battery alert, but it was probably not far from it. I installed Lithium AA batteries in all 3 smoke alarms. I did not use the Duracell AA batteries that came with them. I would strongly suggest doing the same. The Lithium batteries will last far longer, and if they do become depleted, they won’t leak like alkaline. The Lithium batteries claim between 10- and 20-years shelf life, which is basically close to what they are in a backup use. They shouldn’t have any significant drain at any point, and only light drain when the power is out. So, they should last the life of the smoke alarm. To me it is easily worth the roughly $2 per cell, or about $4 per alarm not to have to get up on a ladder for the life of the alarm. I also definitely didn’t want to put Duracell alkaline batteries in a device that is safety critical. Whatever you do, I would suggest not using the included Duracell batteries. I’m not sure what changed with Duracell. Historically I’ve had Duracell batteries in devices for up to 20 years and they still worked! At least if the batteries died, they didn’t leak and destroy whatever the battery was in. Now I’ve had a package of new Duracell batteries that have cells visibly leaking in the plastic package after less than a year of storage in reasonable room temperatures despite the package claiming something like 10 years of shelf life. I’ve also had Duracell batteries leak in the package kept in a refrigerator, so that doesn’t seem to help. Duracell has definitely earned the name of Duraleak that I’ve seen online by others. For important devices I’ve started using Lithium AA cells. I’ve also recently purchased a package of Amazon Basics alkaline for less critical applications. It is too soon to say how they last, although I have had good results with the batteries included with Amazon Fire TV remotes. The status LED normally lights green when the smoke alarm is receiving AC power and functioning normally. It lights red, or flashes red to identify faults or the latching alarm indication. This would be good if you could actually see the LED from the ground. The smoke alarms are located on walls just below the ceiling. This is where the builder installed them initially. There is a small hole to see the recessed LED. This results in a very narrow viewing angle. When mounted on a wall up by the ceiling the angle is such from the ground the LED simply cannot be seen. Not at all. This is a pretty horrible design. Either the hole should be larger or the LED extended further out. If the alarm is mounted on the ceiling and faces straight down this won’t be an issue, but that isn’t the way the builder installed them in my home. As this had to pass inspection, I expect that this meets building code, and I’m positive many other homes are built the same way. The battery drawer can be difficult to open. There is an opening where you insert your finger and pull it out. However, when it breaks free and comes out the nail on your finger gets crunched painfully. This is even worse if you are up on a ladder to change the battery. This isn’t a great design. Again, using a Lithium battery mitigates this somewhat. The single test button is not very responsive. It seems that you need to press it pretty hard and for at least a couple of seconds for it to respond. Pushing it quickly does nothing. If you press it hard and a bit longer it will make an initial chirp followed by an alarm locally and to all interconnected alarms. Remember this when you are up on a ladder to access it in the middle of the night when an alarm goes off. This too could be better. As I wrote above, these smoke alarms were the best I could find so I bought them. It seems absurd that in 2024 there aren’t better connected options. When I can buy a smart WiFi connected multi-color LED smart light bulb for around $10, why aren’t there better options for smoke detectors? Yes, there is Nest that is connected, but it isn’t as good a smoke detector, and the interconnect is proprietary. It would be great to have a connected alarm that I could silence from a smartphone app, or get a smartphone alert in the event of an alarm. It would be great to have this same alarm with connected smart features. I was not able to find such an alarm, so I replaced the alarms I bought 11 years ago with the same alarm. It also seems absurd to use primary batteries for backup power on an AC line powered alarm. Why aren’t there rechargeable batteries that are charged by the AC line? Smoke alarms are intentionally installed up in high locations where access requires a ladder, or more. Expecting people to access the alarm directly to silence an alarm or perform periodic maintenance of changing a primary cell battery that will die and leak is really absurd today. This could be far better, but again it is the best I could find so I bought them again. By installing Lithium batteries that should last the lifetime of the alarm and won’t leak I at least eliminate that issue. In summary, this alarm seems to be the best option available for the most important function: providing an alarm in the event of smoke or fire. The dual ionization and photoelectric sensing provide the best options for detecting different types of fire. Ultimately, this is the most important feature and it does this well. It is also relatively easy to install (especially if replacing the same model). It includes Duracell batteries that I strongly recommend not to use, and invest in some Lithium AA cells. As for convenience features and something that has more modern convenience features it falls far short. There doesn’t seem to be a better option though, so buy this one until something better is available. ... show more
Reviewed in the United States on December 19, 2024 by TechPicky
    • Great detector with two types of technology and a 10-year battery.
Style: Precision Detection Size: 1-Pack Configuration: 10-Year Battery
We enjoy the peace of mind that having dual-function smoke alarms provides. This alarm does both photoelectric AND ionization detection. One if better for slow, smoky fires and the other for faster hot fires. I don't remember which is which, but Google it and remind yourself. This alarm doesn't do carbon monoxide or other gas detection, but we have a separate alarm for that. Finally, possibly the best part, this has a ten-year battery. With regular detectors, you have to change the battery from time to time AND you have to keep track of when you put the thing up (because the detectors all have a ten-year life, even if you regularly replace the battery). So, rather than try to remember when we put up the detector, we just wait for the thing to beep (if we even live here in 10 years) and replace the whole thing at once. It's great. ... show more
Reviewed in the United States on February 26, 2025 by molaw

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