Universal Security Instruments

Model # MCND401B

Internet # 203367046

Plug-In Combination Carbon Monoxide and Natural Gas Alarm

$35.92 /each
  • 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

Frequently Bought Together

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

Info & Guides

You will need Adobe® Acrobat® Reader to view PDF documents.  Download a free copy from the Adobe Web site.



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) 
Connector/Contact Type 
Fixed or portable 
Gas(es) detected 
Carbon monoxide 
Minimum detection (ppm) 
Power Source 
Response time (sec.) 
Voltage (volts) 

Warranty / Certifications

Certifications and Listings 
1-UL Listed 

More Products With These Features


Customer Questions & Answers

2 Questions2 Answers

Customer Questions & Answers

Plug-In Combination Carbon Monoxide and Natural Gas Alarm
Plug-In Combination Carbon Monoxide and Natural Gas Alarm

Ask your questions. Share your answers.

Clear Search Term
Sort By:
1 answer

What is the warrantee period on this unit

This question is from Plug-In Combination Carbon Monoxide and Natural Gas Alarm
Asked by
Ontario Canada
Read all my Q&A
January 28, 2016
0out of 0found this question helpful.
Was this helpful?helpful0unhelpful0

Answer (1)

February 18, 2016
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.
0out of 0found this answer helpful.
Was this helpful?helpful0unhelpful0
1 answer

red power button blinking

This question is from Plug-In Combination Carbon Monoxide and Natural Gas Alarm
Asked by
Read all my Q&A
December 22, 2015
Not sure what this means. Does it need a new battery?
0out of 0found this question helpful.
Was this helpful?helpful0unhelpful0

Answer (1)

Asked by
Long Island, NY
Read all my Q&A
Home Improvement Profile: DIYer
May 25, 2016
Don't waste your time with customer service, trash it.
0out of 0found this answer helpful.
Was this helpful?helpful0unhelpful0
1 of 1
  • 2016-07-25 T21:18:31.693-05:00
  • bvseo_lps, prod_bvqa, vn_prr_5.6
  • cp-1, bvpage1
  • co_hasquestionsanswers
  • loc_en_US, sid_203367046, prod, sort_default
1 of 1
  • bvseo_sdk, java_sdk, bvseo-3.1.1
  • CLOUD, getContent, 249ms

Customer Reviews

Rated 3.3 out of 5 by 12 reviewers.
Rated 4.0 out of 5.0 by 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. December 8, 2015
Rated 2.0 out of 5.0 by Not as advertised Battery stated on package was an Ion battery but all I got was a regular 9 v August 25, 2015
Rated 5.0 out of 5.0 by A must have for your home! I had given this alarm to my daughter and her family several years ago. Two weeks ago the alarm started going off and the word GAS was shown on the digital display. The firemen checked out their home and found a gas leak in their oven and a problem with their furnace. Yes, both at the same time. I bought this alarm to replace the older one per the advice of the firemen. This is the only brand I would buy. I have two of them in my home and have given them to my sisters as well. November 11, 2014
Rated 1.0 out of 5.0 by Not a reliable product. Gave a false natural gas alert. Not a reliable system. I recommend looking for a alternate alarm option. March 1, 2015
Rated 1.0 out of 5.0 by 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 on..no alarm. I bought this from HD despite having big doubts over whether it works...Perhaps the guy got a bad one...it 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. September 2, 2013
Rated 1.0 out of 5.0 by 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- December 4, 2014
Rated 4.0 out of 5.0 by It works, I'm not an expert, but it's easy It plugs into an outlet and does the job of monitoring gas levels and CO. I have it in the downstairs hallway and it is very loud, so it should wake up most of the house if there is danger. We had an incident before I bought the detector and a cook-stove was not turned off all the way, so it leaked gas the whole day downstairs and I couldn't smell it upstairs, however when my husband came home, he could smell the gas from outside and told me to put my coat on and my baby's coat on and to get outside. We're very fortunate that the old house was drafty and didn't blow up. March 12, 2013
Rated 1.0 out of 5.0 by just plane junk!! this unit is just plane junk i would not trust it to protect my life December 23, 2014
  • 2016-07-24 T20:29:55.567-05:00
  • bvseo_lps, prod_bvrr, vn_prr_5.6
  • cp-1, bvpage1
  • co_hasreviews, tv_12, tr_12
  • loc_en_US, sid_203367046, prod, sort_default
2 >>
  • bvseo_sdk, java_sdk, bvseo-3.1.1
  • CLOUD, getContent, 224ms