First Alert CO400B Carbon Monoxide Detector
- Battery powered, 9V battery named in the title
- Electrochemical CO sensor
- Silence feature and end of life signal
- Tamper resistant locking pin
- 3.2 oz, metal enclosure
Updated 23 days ago · Based on the Amazon listing and published specifications, not hands-on testing.
A battery-powered carbon monoxide alarm that adds a silence feature and a replacement warning. Whether a battery ships in the package is unclear, so confirm before counting on it.
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ASIN: B0179NNVIIModel: CO400B
Overview
Not a plug-in or hardwired alarm, the First Alert CO400B runs on a battery and detects the gas with an electrochemical element. A metal enclosure houses it, and a locking pin discourages removal.
An end-of-life signal tells the owner when the unit itself must be replaced, and a silence feature is built in. The limitation is sparse documentation: alarm volume, sensor life and certifications are absent.
Who it's for
Renters and homeowners adding carbon monoxide coverage near sleeping areas without an electrician will find the battery design simple. Buyers who need documented certification details should read the maker's manual first.
Pros and cons
- Battery powered, no wiring
- Electrochemical CO sensor
- End of life signal
- Tamper resistant locking pin
- Battery inclusion unclear
- Alarm volume not listed
- Certification details absent
Performance notes
An electrochemical sensor reacts to carbon monoxide in the air around it, so placement and airflow decide how fast it responds. The audible alarm sounds at its threshold, and the silence feature quiets it while the cause is checked. The locking pin makes casual removal harder.
Specifications
| Brand | First Alert |
|---|---|
| Model | CO400B |
Frequently asked questions
Does the First Alert CO400B come with a battery?
The title mentions a 9V battery, but the product data does not confirm it is included. Check with the seller.
Is the First Alert CO400B a plug-in detector?
No. It is listed as battery powered.
What does the end of life signal do on the CO400B?
The description lists an end of life signal that gives audible notification the unit needs to be replaced.
Can the First Alert CO400B be tampered with?
The description lists a tamper resistant locking pin.