3120B Hardwire Dual Sensor Smoke Alarm with Battery Backup

SKU: 3120B

3120B Hardwire Dual Sensor Smoke Alarm with Battery Backup

SKU: 3120B


The First Alert® Hardwired Dual Sensor Smoke Alarm with Battery Backup is designed to provide peace of mind. The photoelectric and ionization sensors alert you to both smoldering and fast-flaming fires, offering comprehensive detection and early warning. The 85-decibel fire alarm can also connect to other compatible hardwired fire detectors for larger spaces.

  • Photoelectric and ionization sensors provide comprehensive fire detection
  • A single button makes alarm easy to test, or silence during a false alarm
  • Hardwired alarm includes battery backup for detection during power outages
  • Connect with other compatible hardwired alarms to create a safety network
Product Overview


Dual Sensors Detect Two Kinds of Fire

The First Alert 3120B Hardwired Dual Sensor Smoke Alarm features photoelectric and ionization sensors. The photoelectric sensor detects smoldering fires from objects like cigarettes burning on furniture or in trash cans, while the ionization sensor detects fast-flaming fires like kitchen grease fires or combustibles. The dual sensors help provide you and your family with an early warning.

Designed for Fewer False Alarms

Smoke from cooking or even shower steam can sometimes set off a smoke alarm. The photoelectric sensor on the First Alert 3120B Hardwired Dual Sensor Smoke Alarm is sensitive to smoldering fires while reducing false alarms. The photoelectric sensor can also distinguish real threats from everyday activities, resulting in fewer false alarms.

Battery Backup for Detection in a Power Outage

The fire detector is hardwired, but it also features a battery backup to help ensure the photoelectric and ionization smoke alarm can still function in the event of a power outage. The fire detector requires two AA batteries, and features a low-power indicator to alert you when they need to be replaced. A one-touch silence/test button makes it easy to test the detector or silence it during a false alarm.

Interconnectivity for Larger Spaces

The First Alert 3120B Hardwired Dual Sensor Smoke Alarm with battery backup easily connects to other compatible hardwired alarms (sold separately), making it the ideal solution for larger buildings such as institutions, dormitories, hotels, and other multi-family dwellings that use single-station smoke detectors.

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Product Manuals

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User Manual for 3120B Hardwire Dual Photoelectric and Ionization Sensor Smoke Alarm (English, Spanish)

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More Information on Ionization vs. Photoelectric Smoke Alarms