Model # MCND401B

Internet #203367046

Universal Security Instruments Plug-In Combination Carbon Monoxide and Natural Gas Alarm

Universal Security Instruments

Plug-In Combination Carbon Monoxide and Natural Gas Alarm

  • 9 out of 10 carbon monoxide incidents take place in the home
  • Natural gas leaks can be undetecable by the sense of smell alone
  • One installation protects against two deadly threats
$3855 /each
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Product Overview

Offering single installation and double protection, this compact plug-in alarm is perfect for new or replacement installations. The dual sensing alarm provides protection against two deadly household threats, carbon monoxide and natural gas, with a display screen that shows the level of carbon monoxide detected. This alarm is suitable for installation in houses, apartments and mobile homes. Early warning of carbon monoxide and natural gas is best achieved by installing combination alarms on every level of your dwelling, including basements. For maximum protection, install an alarm inside every bedroom and outside every sleeping area as well.

  • 3 LED colors indicate status of power, carbon monoxide and natural gas
  • Compact design covers only one outlet
  • Ideal for every room in your home
  • Plugs into standard outlet; no additional mounting required
  • Fast and easy to install
  • Backup battery provides protection even during a power outage
  • 9-Volt Eveready alkaline battery included
  • Large, bright digital screen displays carbon monoxide level
  • Click here for more information on Electronic Recycling Programs

Info & Guides

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Name Plug-In Explosive Gas and Carbon Monoxide Alarm with Digital Display Plug-In Combination Carbon Monoxide and Natural Gas Alarm Plug-In Combination Explosive Gas/Carbon Monoxide Alarm Detector with Battery Back-up
Brand First Alert Universal Security Instruments Kidde
Ratings (51) (14) (271)
Alarm Type Carbon Monoxide Carbon Monoxide,Natural Gas Carbon Monoxide,Natural Gas,Propane
Power Source Battery Plug-In Plug-In
Alarm/Detector Features Digital display Battery Back-Up,Digital display Battery Back-Up,Digital display
View Product View Product View Product



Coverage area (sq. ft)
Product Depth (in.)
Product Height (in.)
Product Width (in.)


Alarm Type
Carbon Monoxide,Natural Gas
Alarm/Detector Features
Battery Back-Up,Digital display
Calibration (% of LEL)
Commercial / Residential
Connector/Contact Type
Fixed or portable
Gas(es) detected
Carbon monoxide
Minimum detection (ppm)
Pack Size
Power Source
Response time (sec.)
Voltage (volts)

Warranty / Certifications

Certifications and Listings
1-UL Listed

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Customer Questions & Answers

What is the warrantee period on this unit

Asked by: Carolyn
Thank you for your recent inquiry with The Home Depot, Carolyn. This alarm has a five year limited warranty, you can view all of the details here: We appreciate your business and look forward to serving you in the future. Thank you for shopping Home Depot.
Answered by: THDSupport
Date published: 2016-02-18

red power button blinking

Not sure what this means. Does it need a new battery?
Asked by: Bucky
Don't waste your time with customer service, trash it.
Answered by: Phil
Date published: 2016-05-27

what does it mean when the blue light keeps flashing. i dont smell anything or no alarm goes off...

what does it mean when the blue light keeps flashing. i dont smell anything or no alarm goes off . so is that normal
Asked by: skip

Our alarm sounded because of gas. How do we turn off the alarm?

Our alarm sounded because of gas. How do we turn off the alarm?
Asked by: sam
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Customer Reviews

Plug-In Combination Carbon Monoxide and Natural Gas Alarm is rated 3.5 out of 5 by 14.
Rated 1 out of 5 by from Don't count on this to detect Natural Gas! google the model# MCND401B and look at the reviews on Amazon...the first on has a video of guy waving this "Natural gas" alarm over an unlit stove with the gas alarm. I bought this from HD despite having big doubts over whether it works...Perhaps the guy got a bad happens. When I got the alarm, I pulled the tag blocking the battery, pushed the test buttons to confirm it was live and replicated the test in the video...waving the alarm directly over an unlit burner with gas gushing out. Narry a peep from the alarm...just like in the video. Back to HD it went.
Date published: 2013-09-02
Rated 1 out of 5 by from Not a reliable product. Gave a false natural gas alert. Not a reliable system. I recommend looking for a alternate alarm option.
Date published: 2015-03-02
Rated 1 out of 5 by from horrible product I purchase 20 of these units and 6 have went bad within the past year. I've contacted USI electronics customer service on multiple occasions and their only solution is send it back. That's after I contacted them 3 or 4 times. Stay clear of this product. It will go off at odd times for no reason. VENTTEX Inc. -an off duty fireman company-
Date published: 2014-12-04
Rated 4 out of 5 by from Great alarm, I like the combination! I like that this alarm also has a natural gas alarm. My son has health challenges with his endocrine system, lack of smell is a part of his diagnosis. Last year when undergoing testing at the National Institutes of Health in Bethesda MD, they discovered my son has no nerve bundle from the olfactory bulb to the hypothalamus so medically / physically he has no sense of smell. If there was a gas leak he would be unable to smell it. So I really need to order some more of these for other areas of the house. I like the size of this unit - it is compact and lighter than my older one. Stays plugged into the receptacle nicely because of it's lighter weight.
Date published: 2015-12-08
Rated 5 out of 5 by from Just what we needed! Every home should have one, but we bought this one specifically for my elderly mother's home because she has lost her sense of smell. We were concerned she would not smell gas if there was a leak. This unit was easy to install and is very inconspicuous.
Date published: 2016-12-20
Rated 1 out of 5 by from just plane junk!! this unit is just plane junk i would not trust it to protect my life
Date published: 2014-12-23
Rated 2 out of 5 by from Not as advertised Battery stated on package was an Ion battery but all I got was a regular 9 v
Date published: 2015-08-25
Rated 5 out of 5 by from Natural Gas Alarm This is one of the few products I found that is small and monitors natural gas as well as carbon monoxide. You just plug it in. Luckily I have not had to test it in a real situation, but the alarm itself is very very loud so easily awakens even the deepest sleeper.
Date published: 2016-08-09
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