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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 1 left in stock, order soon!
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Arrives Tuesday, Sep 9
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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: Tuesday, Sep 9

This item is non-returnable:

Non-returnable. Transportation of this item is subject to hazardous materials regulation

View our full returns policy here.

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Similar Products

Top Amazon Reviews

    • 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
    • Easy install
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
Works as described
Reviewed in the United States on August 30, 2025 by J.B
    • Excellent product (but marred by one manufacturer defect) - and some interesting installation advice
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
Review Image by Ralph B Ralph B
There's good news and bad news about this product. (Detailed review ahead.) This product is highly rated by the leading consumer testing magazine. And it's priced competitively on Amazon. I ordered 6 of these, and all arrived promptly, packed together, but in individual smaller boxes, all well cushioned. Five of the items arrived perfect, and installed easily (but more info on an important installation detail below). One of these detectors arrived with a significant manufacturer's defect. See the attached photo for a clear illustration of the defect, which made this detector uninstallable. The electrical pins inside the device were improperly positioned. This defect also interfered with the opening/closing of the battery door on the new detector. Amazon handled the exchange promptly and courteously. Now, about the installation of the OK units: There's also good news and bad news. Good news: The connecting pigtails included with the new First Alert smoke detectors are identical to the pigtails in my 10-year-old First Alert same-model detectors, which these are replacing. That means it was not necessary to un-wire and re-wire new pigtails into their wall boxes before replacing each detector. I was able simply to disconnect the old pigtail from the old detector and plug it into the new detectors. Easy! And safe! Bad news: First Alert has very SLIGHTLY modified the round plastic mounting base for the new units, compared to their own 10-year-old design. This means I had to remove the old mounting base and replace it with the new one. It's an easy step, no problem. But because the new mounting base has a smaller diameter (a "trimmer" design), the new bases expose a ring of unpainted/unwalpapered wall/ceiling surface, which requires patching. First Alert has ALSO SLIGHTLY modified the turnscrew plastic locking design of the detector, so it no longer secures completely to the 10-year-old design. This, also, means the old mounting bases cannot simply be left in place, with the new detectors simply attaching to them. In a couple of highly-visible and not-easily-patched wallpaper locations, I decided to leave the old mounting bases in place anyway (preserving the wallcovering's appearance), and discovered that the new detectors ARE able to hang fairly securely (but not perfectly) on the old bases. This is an imperfect workaround, but it DOES work, especially since the detectors are in no danger of falling off the wall (they're hardwired, electrically). Using this method will require a bit of care (a two-handed job) when changing batteries annually, to avoid pulling the detectors off their mounts. But it's not difficult. A final note: Regardless of whether these detectors are attached to their OLD mounts or to the NEW ones, the distinction is invisible from below. In fact, the wallcovering issue with the new, trimmer bases is more noticeable than the new detectors attached to the old mounts. ... show more
Reviewed in the United States on January 12, 2018 by Ralph B Ralph B
    • 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
    • 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
    • Going back to Kiddie. Always chirping but never consistent
Style: Standard Detection Size: 1-Pack Configuration: 10-Year Battery
I have had these units for over a year now and they are driving me insane! I decided to replace all the original smoke detectors in my house which was built in 1996. Upon completing research, I found that Consumer Reports rates these units as the best smoke only units on the market, so I went with them. Install was seamless, replaced the pigtails and connected to house electric, no issues. About an hour after installing them, the unit in my daughters room chirped 3 times and then five minutes later it did it again, and then nothing for a couple of hours and then it did it again, 3 chirps, and then silent for the rest of the day. The next day, I heard 3 chirps come from the guest room, silent for about 15 minutes, and the 3 more chirps, then nothing for several more hours. This same issue repeats itself in the master bedroom, and my son's room (all units on the upper level of our house). According to the owner's manual, 3 chirps every five minutes means a malfunction and you should replace the unit immediately. I had just barely purchased the units and they're already malfunctioning? My issue with this is that it isn't happening every five minutes, it is completely a guess when the next chirp will be. And besides, none of the units on the main floor or basement were chirping. I replaced batteries on all units, I even undid the wiring and re-installed all the units and received the same result. I finally called First Alert and they walked me through some troubleshooting exercises and they determined that the smoke detectors are in good working condition and that there must me an issue with how my house was wired. Well, now it is one year later and the smoke detectors are still doing their thing, never consistent but I have had enough..I am switching to Kiddie brand to see if the issue continues. If it does, I will get an electrician to check it out. First Alert smoke detectors are no bueno for this house. I have 5 units on my second story and all 5 of them give a ... show more
Reviewed in the United States on October 4, 2021 by Kel

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