BRK 9120B Smoke Alarm, Dual Ionization, 120V Hardwired w/ Battery Backup

by BRK
$ 8.49
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This BRK/First Alert 9120B dual ionization, 120v hardwired w/battery back-up smoke alarm is a great choice when it comes to affordability and design.

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Redesigned, BRK created the 9120B model to directly replace past BRK smoke alarms while greatly improving sensing technology, installation ability, and improved connectivity. The first alert 9120B smoke alarm has an 85dB horn, 9V battery back-up, and a silence feature.

The BRK 9120B smoke alarm uses dual ionization technology to reduce false alarms more efficiently and more accurately than ever before. The 9120B smoke alarm is designed for sleeping rooms in your home, hospitals, hotels, motels, college dormitories, and multi-family housing units. This BRK smoke alarm complies with NFPA101, UL217, CSFM, NFPA72, HUD, FHA, and other agencies. Where AC/DC silent smoke alarms are required, BRK smoke alarms work perfectly.

The BRK 9120B model has the ability to be interconnected within a circuit of alarms and other alert devices such as bells, whistles, repeaters, fans, or switches. You can connect up to 17 BRK devices of which 11 can be smoke alarms, and 6 can be alternate devices! Integrated within the BRK 9120B smoke alarm is a 9V battery backup to make sure your smoke alarm does not loose operation when power fails which provides added security and peace of mind.

All around, BRK smoke alarms are the perfect choice if you are looking for affordability, function, and ease of use.

BRK Smoke Alarm Replacement

This BRK Electronics 9120B smoke alarm is the direct replacement for the discontinued BRK smoke alarm models 4120B, 4120SB, 4919 and 86RAC. Wiring harness and communication protocol is the same across BRK models (i.e. a 4120B will talk to a 9120B). When replacing an older smoke detector, only the mounting bracket needs to be changed.

Smoke alarms all have expirations dates. We only sell alarms that are current. If you need a specific expiration date please contact us so we can get you exactly what you need.

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*Search Terms

- Hardwired Smoke Alarm

- Hardwired Smoke Alarm 120v

- Replacement model for 41208, 4120B

41208 4120b


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  • How do you change the battery??


    Great question please see images below to change the battery.

    To change the battery if you hold the face of the 9120B smoke alarm towards you, to the left hand side there is a litttle compartment with a button looking latch similiar to a back of a tv remote control that you have to press/pull and the compartmnet of the 9 volt battery will rotate out. Hopefully this helps you out. Feel free to reach out via email and we will be happy to reach out to you. We can send you a video or troubleshoot over the phone.

    Please click below to vie images.

    BRK 9120B Image 1

    BRK 9120B Image 2  

    BRK 9120B Image 3

    Thank you,

    JACE Supply LLC
    Sales/Customer Service
    P: 502-305-2891