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BRK Electronics First Alert 4120B 120V AC/DC Hardwired with 9V Battery Backup Ionization Smoke Alarm (Upgraded to 9120B)


When ordering this, we will upgrade to a current model, a plug-n-play unit. You only need to change the mounting bracket.

Our Price: $15.96
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Model: BRK-4120B

Technical Spec Downloads
Technical Spec

BRK 4120B Smoke Alarm AC Powered with Battery Back-up. Designed for the fastest possible installation! If AC power fails, the battery back-up keeps the smoke alarm working.

  • Ionization Sensor
  • Quick Plug-In Power Connector
  • Alarm Indication
  • Battery Drawer Lock
  • Mounting Bracket Lock
  • Swing-Open Battery Door
  • Battery Activation Tab
  • Battery Back-Up
  • AC Power Indicator
  • Low Battery Warning "Chirp"
  • Missing Battery Tab
  • 9V Battery Included
  • 10-Year Limited Warranty On Alarm
Model # 4120B
Operating Voltage 120V AC 60Hz w/ 9V battery backup (4120B only)
Interconnections Up to 11 additional BRK smoke detectors and 6 compatible devices such as bell, repeaters, or switches.
Listing UL Listed to U.S. and Canadian safety standards

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