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Internet # 202220507

Model # 21010620

Store SKU # 1000037811

Firex Plug-in Carbon Monoxide Detector, 9V Battery Backup, Digital Display (6-Pack)

Includes 6 units
$229.97
($38.33 /unit)
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  • Carbon monoxide detector plugs directly into wall outlet
  • 9V battery backup for protection even during power outages
  • Digital display updates CO level in PPM every 15 seconds
  • View More Details

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Product Details

About This Product

The Kn COPP 3 is a plug in carbon monoxide alarm provides you and your family with warning signal to protect against dangerous levels of carbon monoxide in your home. This alarm is easily installed in any of your AC wall outlets. The digital display feature allows for easy viewing of carbon monoxide levels from 30-999PPM (parts per million).

Highlights

Product Information

Internet # 202220507

Model # 21010620

Store SKU # 1000037811

Specifications

Dimensions

Product Depth (in.)

1.75 in

Product Width (in.)

3.75 in

Details

Alarm/Detector Features

Battery Back-Up, Digital display, Hush Button

Alert Type

Siren

Battery Type Required

9-volt

Commercial/Residential

Home

Included

Batteries

Pack Size

6

Power Source

Plug-In

Returnable

90-Day

Voltage (V)

120

Warranty / Certifications

Certifications and Listings

UL Listed

Questions & Answers

How much sq ft does one detector cover
ByJun 18, 2026
1 Answer | 
Answer This Question

Hello. It does not cover a square footage. It covers a location in a residential house. Our alarms are not rated for commercial use or use in an attic or garage. CO alarms should be mounted in or near bedrooms and living areas. It is recommended that you install a Kidde CO alarm on each level of your home. When choosing your installation locations, make sure you can hear the alarm from all sleeping areas. If you install only one CO alarm in your home, install it near bedrooms, not in the basement or furnace room. Improper location can affect the sensitive electronic components in this alarm. To avoid causing damage to the unit, to provide optimum performance, and to prevent unnecessary nuisance alarms: Do not install in kitchens, garages or furnace rooms that may expose the sensor to substances that could damage or contaminate it. Do not install in areas where the temperature is colder than 40°F (4.4°C) or hotter than 100°F (37.8°C) such as crawl spaces, attics, porches and garages. Do not install within 5 ft. of heating or cooking appliances. (Kidde recommends 15 ft. to prevent nuisance alarms). Do not install near vents, flues, chimneys or any forced/unforced air ventilation openings. Do not install near ceiling fans, doors, windows or areas directly exposed to the weather. Do not install in dead air spaces, such as peaks of vaulted ceilings or gabled roofs, where CO may not reach the sensor in time to provide early warning. Do not install on a switched or dimmer-controlled outlet. Do not install this unit near deep-cell large batteries. Large batteries have emissions that can cause the alarm to perform at less than optimum performance. Do not obstruct the vents located on the alarm. Do not place the alarm where drapes, furniture or other objects block the flow of air to the vents.

By|Jun 22, 2026


    I want to know what is the ppm number that this will alarm at?
    ByMar 16, 2026
    2 Answers | 
    Answer This Question

    I wish you would make a more sensitive one, such as in this picture: 40-60 ppm CO instantly triggers yellow light and 3 second alarm. 65-95 ppm CO instantly triggers red light and continuous alarm. You can meet a higher standard than the minimum.

    By|Jul 30, 2026

      (2)

      Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure.

      By|Mar 18, 2026


        If the alarm only goes off at "dangerous levels" 70ppm, many people can die if there's a slow leak. ie at 30-40ppm. Especially at risk are children and older adults. Why aren't these questions being answered?
        ByMar 4, 2026
        2 Answers | 
        Answer This Question

        Hello. These units are tested at the UL 2034 standard for residential carbon monoxide alarms. They have not been investigated for carbon monoxide detection below 70 PPM.

        By|Mar 9, 2026

          Correct. At 70ppm you have already been exhibiting signs of co2 poisoning, or worse unconsciousness or dead. I dont need an alarm to tell me I'm near death. These should sound an alarm at half that value.

          By|Jul 26, 2026

            (10)

            At what level of CO2 (PPM) will cause the alarm to go off?
            ByMar 1, 2026
            1 Answer | 
            Answer This Question

            Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure

            By|Mar 9, 2026


              What is the level of co the alarm sounds at?
              ByFeb 28, 2026
              1 Answer | 
              Answer This Question

              Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure

              By|Mar 9, 2026


                What CO level triggers the alarm?
                ByFeb 28, 2026
                1 Answer | 
                Answer This Question

                Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure

                By|Mar 9, 2026


                  Will the alarm go off at 30ppm? Or only once it reaches 70ppm?
                  ByFeb 27, 2026
                  1 Answer | 
                  Answer This Question

                  Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure

                  By|Mar 9, 2026


                    what is the alarm level?
                    ByFeb 22, 2026
                    1 Answer | 
                    Answer This Question

                    Hello. This unit conforms to UL 2034 standards. At 70 parts per million parts of air, PPM, it will go off after 1 to 4 hours of continuous exposure. At 150 PPM, it will go off after 10 to 50 minutes of continuous exposure. At 400 PPM or higher, it will go off after 4 to 15 minutes of continuous exposure

                    By|Mar 9, 2026


                      Viewing 1-8 of 92

                      Customer Reviews

                      4.7 out of 5

                      • 4.7 out of 1,032 reviews
                      • 94% recommend this product
                      Filter by:
                      Showing 1-10 of 1,032 reviews
                      Kiddie carbon monoxide alarm defective
                      My device is dated Feb 2020. It’s only been 6 years and is chirping non stop. Changed batteries and nothing. Have 5 other devices purchased at same time. This is only one that is defective.
                      by
                      Response from Kidde ExpertJul 16, 2026
                      Thanks for your message and for reaching out to Kidde. A chirp every 60 seconds is the alarm’s low-battery alert. Please install fresh, approved batteries and press and hold the Test/Hush button until the alarm sounds (i.e., reset alarm) to confirm operation. If the chirp continues after replacing the batteries and resetting the alarm , please contact Kidde Customer Support at 1-800-880-6788 so we can assist further.
                        Kidde's quality control is apparently slipping
                        This is the second CO detector I received from Kidde in the last two months that had an issue. The first one was delivered in a plastic bag, directly from the manufacturer, and it had obviously been used and tampered with. There was no paperwork, no battery, no packaging, just a cellophane bag holding the unit. When looking at the back of it, I could clearly see where it had been plugged in and electrically arced across the power blades. It was also evident the sticker which covers the screw holding the two halves together had been punctured. When I ejected the power supply, you cold see it was an older model than the one on the other new detector I had purchased a few days earlier. I was refunded for that used detector. Yesterday, the replacement I purchased arrived in official KIDDE packaging untampered with. However, when I opened it today and went to install the battery, touched it to my tongue and barely felt anything. When I looked at it, I could see the battery was leaking from one of the posts. This is a brand new battery. The date on the bottom is 05 2028. I've been using their products for years and had nothing other than perfect experiences until the last two months. Really hoping this isn't a trend.
                        by
                        Response from Kidde ExpertMay 14, 2026
                        Thanks for your message and for reaching out to Kidde. We can help determine whether your alarm is covered by a recall or warranty. Please call our team at 1-800-880-6788 and we’ll review options and next steps with you.
                          1 found this review helpful
                          Old Product
                          I bought this unit Monday delivered on Tuesday and the manufacture date is 4 years ago 12-08 2021 why would I be sent a unit that has been sitting somewhere for that long.Maybe there have been updates my unit should at least be from 2025 This is the 4th unit I have purchased over the years for my house Thank You
                          by
                          Response from Kidde ExpertDec 31, 2025
                          Hi Ken, thank you for sharing your experience. If there’s anything we can assist you with regarding our Kidde products, please don’t hesitate to call us at 1-800-880-6788 or email us at Kidde.product.support@kgsolutions.com.
                            1 found this review helpful
                            Stay away.. Worst customer support
                            STAY AWAY FROM THIS COMPANY… The most horrible and nasty customer service agents ever… I called to get a replacement for a CO alarm that went bad after couple of years and they made me go through hoops to agree to send a replacement and they do not send any update regarding your order or replacement and you have to call to get update Aside from that, both times I called, the customer service ladies who answered both calls were extremely rude and nasty and one of them hung up after she told me it will take 15 days to just process the order and when I said “wow that’s a long time”, her reply was “that’s everything I have” and hung up on me
                            by
                            Response from Kidde ExpertJul 10, 2025
                            Thank you for taking the time to share your experience with us, Moe. We’d like the opportunity to discuss your concerns in more detail. Please email us at Kidde.Social.Care@carrier.com, so we can conduct a thorough investigation.
                              1 found this review helpful
                              We have had a carbon monoxide detector that does not have a digital display and we have had it go off several times. Since there is no readout we error on the side of caution and have the Fire Department come out on a non-emergency run and bring their sniffers and check the house to insure that we are safe only to find that the batteries we used were depleted. A long time ago we had a digital detector in our house and it went off and showed numbers. A call to our neighbor that was a captain on the Fire Department told us to leave the house and call the Fire Department. Upon arrival they found the carbon monoxide levels extremely high and upon further investigation it was found that our heat exchanger in our furnace had malfunctioned. If we had ignored this alarm I would not be setting here to right this review. We have gone back to all digital display detectors in our new house. Like I said the non readout one caused us grief and has been properly disposed of and replaced with these digital readout ones. I feel more confident with these alarms in our house and sleep sounder knowing that of the 4 alarms that we have we are fully protected. I highly recommend these detectors. We give them to people that are moving into their first home as a house warming gift.
                              by
                              • Verified Purchase
                              2 found this review helpful
                              Rating provided by a verified purchaser...
                              Rating provided by a verified purchaser
                              by
                              • Verified Purchase
                              Love this monitor, it cycles ever so often and displays the reading. Also, plugs into an outlet s...
                              Love this monitor, it cycles ever so often and displays the reading. Also, plugs into an outlet so no batteries to go dead. Purchased a couple of weeks ago.
                              by
                              • Verified Purchase
                              2 found this review helpful
                              I read that there is an internal clock that limits the unit to seven years of service and just pu...
                              I read that there is an internal clock that limits the unit to seven years of service and just pulled mine because I'm getting a chirp and low battery indication. It was manufactured 8/13/98 and had been displaying 0 ppm CO and flashing the decimal point to indicate operation. If the expiration clock feature is true, it must have been added after I purchased mine. The model number is 900-0076-00 and there are no expiration instructions on the unit. Other than battery replacement, the unit requires no special attention and hasn't even collected dust. Speaking of battery replacement, that is a weak point. Applying pressure to the access panel and sliding in the direction of the arrows may not work as well as prying it loose with a screwdriver. There is a remote, wired mounting option but I chose to plug the unit directly into an outlet. Very easy installation - plug and play. My old unit looks exactly like the one pictured but with a bit of yellowing on the front face at the power transformer location. I guess it's time for a replacement and unfortunately, electronics go to the landfill.
                              by
                                • Recommended
                                3 found this review helpful
                                This is extremely well engineered!!! You can remove the transformer to mount away from a plug, o...
                                This is extremely well engineered!!! You can remove the transformer to mount away from a plug, or simply plug it into an outlet. It has a small tap at the bottom you can pull out when plugging directly into the wall outlet to compensate for the wall outlet projecting out from the wall to keep it flat. It comes with a battery, so is dual power.
                                by
                                • Verified Purchase
                                • Recommended
                                6 found this review helpful
                                Easy to understand instructions. Easy to get working. The hardest part was getting the unit out o...
                                Easy to understand instructions. Easy to get working. The hardest part was getting the unit out of the plastic packaging.
                                by
                                • Verified Purchase
                                • Recommended
                                1 found this review helpful
                                Showing 1-10 of 1,032 reviews