First Alert 120-Volt AC Smoke Alarm with Lithium Battery Backup-9120LB at The Home Depot
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First Alert

Model # 9120LB

120-Volt AC Smoke Alarm with Lithium Battery Backup

First Alert 120-Volt AC Smoke Alarm with Lithium Battery Backup

This item has been discontinued.
The Home Depot no longer carries this specific product.

$18.88 / each
Item cannot be shipped to the following state(s): AK,GU,HI,PR,VI


In Stock



Model # 9120LB

Internet # 204357244

This alarm is 120-Volt AC inter-connectable (with maximum 18 compatible devices), which lets the alarm be interconnected with up to 12 other compatible smoke alarms and six compatible devices like bells, horns, repeaters, and door closers to network a comprehensive system for your home. If one unit triggers an alarm, all smoke alarms in the series will sound. The alarm comes with a lithium battery backup to make sure the alarm is working at all times. The dust-reducing packaging helps avoid accidental alarms due to contaminants and the 85dB horn can be inspected with a test button.

  • Locking pins deter removal
  • Power indicator lets you see at a glance that the alarm is powered
  • Meets UL standards
  • 10-year limited warranty

Info & Guides

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Alarm Sensor Type  Ionization  Alarm Type  Smoke 
Alarm/Detector Features  No Additional Features  Assembled Depth (in.)  7 in 
Assembled Height (in.)  5.59 in  Assembled Width (in.)  2.25 in 
Battery Back-Up  Yes  Battery Power Type  Lithium Ion 
Battery Size  Lithium Ion  Certifications and Listings  No Certifications or Listings 
Commercial / Residential  Commercial / Residential  Connector/Contact Type  4-Wire 
Digital Display  No  Electrical Product Type  Smoke Detector 
Included  Batteries  Returnable  90-Day 
Voltage (volts)  120 



Most orders process within 3 business days.

Please allow 3 to 5 business days for Standard Shipping in addition to order processing time, which varies by product.  Items deliver by small parcel service.

If product is eligible for shipping to AK, HI and US Territories additional transit time and remote surcharges may apply.