First Alert/BRK 9120B / SC-9120B Hardwired
An older hardwired ionization smoke alarm with 9V battery backup.
DiscontinuedNo longer made or sold new. Specs are kept for comparing generations.
Alarm spec sheet
| Type | Smoke |
|---|---|
| Sensor | ionization |
| Power | Hardwired 120-volt with 9V battery backup |
| Interconnect | Wired |
Listed features
- Interconnects with up to 12 other First Alert or BRK hardwired smoke detectors and 6 other compatible devices
- 9V battery included
Worth checking
- Ionization sensing only
Where to buy the 9120B
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good to know
- Discontinued. You may still find it used or on clearance.
- 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 9120B | |
|---|---|
| Type | Smoke or CO alarm |
| Alarm | smoke |
| Sensor | ionization |
| Power | Hardwired 120-volt with 9V battery backup |
| Interconnect | wired |
Compare the 9120B with
How each closest rival differs from the 9120B, 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
Ask the meadow
9120B: questions answered
From First Alert's published specs, last checked 2026-11-11.
Where should the First Alert/BRK 9120B / SC-9120B Hardwired go?
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 AlertCO400 Battery Carbon Monoxide Alarm
- First AlertCO605 Plug-in Carbon Monoxide Alarm
Where these specs come from
Last checked 2026-11-11. Spot something wrong? Tell us. Read our editorial and safety policy and corrections.