First Alert CO400 Battery Carbon Monoxide Alarm
A battery-operated carbon monoxide alarm with an electrochemical sensor, a single test and silence button and an 85 decibel horn.
Alarm spec sheet
| Type | Carbon monoxide (CO) |
|---|---|
| Sensor | electrochemical |
| Power | Battery operated |
| Interconnect | None |
| UL standards named | Listed to UL 2034 Standard |
Listed features
- Portable
- Single test and silence button
- 85 decibel alarm
Worth checking
- Battery powered only
Where to buy the CO400 Battery Carbon Monoxide Alarm
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- Check for recalls: Search the agency's recall list with the model number and date code from the label: CPSC recall search.
- Use and supervision: follow the maker's warnings on the product, and see CPSC's Safe Nursery guide. Check the label and the maker's instructions, and ask your pediatrician about your child.
Full specs
| First Alert CO400 Battery Carbon Monoxide Alarm | |
|---|---|
| Type | Smoke or CO alarm |
| Alarm | CO |
| Sensor | electrochemical |
| Power | Battery operated |
| Interconnect | none |
| Standards (maker) | Listed to UL 2034 Standard |
Compare the CO400 Battery Carbon Monoxide Alarm with
How each closest rival differs from the CO400 Battery Carbon Monoxide Alarm, from the makers' specs.
- First AlertSMCO210 / SMCO210V ComboCompare side by side
- First AlertSMCO500V ComboCompare side by side
- First AlertSM210 / SM210V / SM210L 10-Year Smoke10-yearCompare side by side
- First AlertSMCO100 / SMCO200V Combo10-yearCompare side by side
CO400 Battery Carbon Monoxide Alarm: questions answered
From First Alert's published specs, last checked 2026-11-11.
Where should the First Alert CO400 Battery Carbon Monoxide Alarm go?
Maker's standards wording: Listed to UL 2034 Standard. Use and supervision: follow the maker's warnings on the product, and see the AAP's safety and prevention pages. Check the label and the maker's instructions, and ask your pediatrician about your child.
Still wondering? Write to us at hello@cribpicks.com and we'll look it up.
More smoke and CO alarms
- First AlertSMICO100-AC Hardwired Combo
- First AlertSMI100-AC Hardwired Smoke
- First AlertSC5 Smart Smoke & CO
- First Alert10-Year Battery Photoelectric Smoke Alarm, Slim Profile
- First AlertCO605 Plug-in Carbon Monoxide Alarm
- First AlertCO710 Carbon Monoxide Alarm with Digital Temperature Display
Where these specs come from
Last checked 2026-11-11. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.