First Alert

First Alert 9120B Hardwired Ionization Smoke Alarm with Battery Backup

SKU 9120B
First Alert 9120B hardwired ionization smoke alarm with replaceable battery backup. Interconnects with up to 18 compatible alarms for whole-home coverage. UL 217 listed. Ideal for detecting fast, flaming fires.
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Smoke Ionization Hardwired + Battery Backup
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First Alert 9120B Hardwired Ionization Smoke Alarm

The First Alert 9120B is a dependable hardwired ionization smoke alarm trusted by contractors and homeowners for decades. Ionization technology responds quickly to fast-flaming fires — the type that can engulf a room in minutes — making the 9120B a critical component of any whole-home fire safety plan.

Key Benefits

  • Hardwired connection ensures continuous operation; replaceable battery backup activates during power outages
  • Ionization sensing detects fast, flaming fires rapidly
  • Fully interconnectable — when any alarm triggers, all connected alarms sound
  • Test/hush button for convenience and weekly testing
  • 85 dB alarm heard throughout the home
  • UL 217 listed

Trusted by professional HVAC and electrical contractors. Easy installation with standard wiring.

Technical Documentation