First Alert

Model # CO5120BN

Internet # 204357249

Battery Operated Carbon Monoxide Alarm with Battery Backup

$29.87 /each
  • Quick plug-in power connector
  • Superior carbon monoxide sensor with battery backup
  • Hardwired with battery backup

Frequently Bought Together

Product Overview

The BRK hardwire carbon monoxide alarm detects dangerous CO gas and allows you peace of mind with its battery backup. This alarm features a controlled microprocessor for few were nuisance alarms and quick plug-in power connector for easy installation. This BRK electronics carbon monoxide alarm is listed to UL safety standards.

  • Superior carbon monoxide
  • Simple to use silence/test button
  • 9-Volt battery included
  • 7-year limited warranty

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 


Alarm Type 
Carbon Monoxide 
Alarm/Detector Features 
Battery Back-Up 
Battery Back-Up 
Commercial / Residential 
Commercial / Residential 
Connector/Contact Type 
Power Source 
Voltage (volts) 

Warranty / Certifications

Certifications and Listings 
No Certifications or Listings 

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Customer Questions & Answers

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Customer Questions & Answers

Battery Operated Carbon Monoxide Alarm with Battery Backup
Battery Operated Carbon Monoxide Alarm with Battery Backup

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1 answer

Battery or Hardwire w/Battery Backup?

This question is from Battery Operated Carbon Monoxide Alarm with Battery Backup
Asked by
Syracuse, NY
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September 12, 2015
Other sites, including BRK, show this to be hardwire with 9v backup. Is this correct?
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Answer (1)

June 19, 2016
I guess it can work both ways. By battery or hardwire with battery back up.I have 12 of them I'm trying to get rid of for 20 dollars a peace.
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Customer Reviews

Rated 4.4 out of 5 by 7 reviewers.
Rated 5.0 out of 5.0 by on-line purchase of article not available in store alarm was a replacement for a part that was eight years old, but your website still had it as an option to purchase (no delivery charge if picked up at my store, an option I choose). an employee at the Salem, MA store recommended I go to the website when it was not available. I do not know his name. March 1, 2016
Rated 4.0 out of 5.0 by Hope it works I simply replaced the previous unit that kept giving a false alarm after 7 years. I never had a CO2 problem, but I believe it would alarm if we had a real threat. December 8, 2015
Rated 5.0 out of 5.0 by CARBON MONOXIDE ALARM Prompt shipping and easy to assemble, I would recommend this product to my friend. January 6, 2015
Rated 4.0 out of 5.0 by CO Monitor This is a replacement unit for one that finally bit the dust. I've got several in my home, and only one failed, after over 10 years. Since they still make the same model, all I had to do it plug it in to the existing frame and wiring. One note: the unit is AC operated (not battery) with battery backup. October 22, 2014
Rated 5.0 out of 5.0 by Carbon monoxide We love this product. We would recommend this product to my family and my friends October 15, 2014
Rated 5.0 out of 5.0 by Direct Replacement This is a direct replacement for the unit that was installed in our home when it was built. The original unit was 13 years old and beginning to fail. It was an easy replacement. March 24, 2014
Rated 3.0 out of 5.0 by Good product, but difficult to connect to mount This is a good product except that it is very difficult to connect to its mounting plate. I screw it in and then I notice it hanging by it's wire sometime later. November 12, 2013
  • 2016-07-24 T18:16:28.374-05:00
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