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Designed to help promote household safety, the First Alert 9120B Hardwired Smoke Alarm with Battery Backup can provide a vital early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires.
Ionization Sensor Reliably Detects Flaming Fires
The First Alert 9120B Hardwired Smoke Alarm with Battery Backup comes equipped with an ultra-reliable ionization sensor to provide the earliest possible warning of a fast-flaming fire. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials.
Gasket-less for Easy Installation
To facilitate hassle-free installation, this smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the alarm secure over a wide rotation range while maintaining perfect alignment. The alarm also comes with a dust cover to keep the unit clean during construction. AC-powered smoke alarms must be installed in accordance with all local electrical codes.
Battery Backup for Detection During a Power Outage
This smoke alarm is designed for hardwired installation, but it also features a battery backup that helps ensure continued functionality in the event of a power outage. The unit comes with a 9-volt battery and features a pivoting, easy-to-access battery drawer that allows you to replace the battery without dismounting the alarm.
Works in Tandem with Other First Alert Alarms
In addition to functioning independently, this smoke alarm can also integrate with up to 12 other First Alert or BRK hardwired alarms for coverage of larger spaces. It also integrates with up to six other compatible devices, such as bells, horns, and repeaters. If one alarm in the series is triggered, they will all sound. The alarm features a latching indicator to identify which unit triggered the alarm, alerting you to the area of danger.
First Alert Smoke Alarm 9120B
Recommended replacement for the following obsolete models:
First Alert SA4120B
First Alert SA4121B
First Alert SA4919B
Average Customer Rating Based on 117 reviews:
Reviewer: Robert Taylor
The alarms were as I had ordered and, although they have not alarmed I believe they will function properly.
smoke alarm - 09/13/2018
Reviewer: Dawn Cinker
Product was exactly the right detector to replace our old one. good email updates on shipment status
Good Response - 09/13/2018
Reviewer: Harry Colvin
Order was received quickly
Smoke Alarm - 09/10/2018
Reviewer: Alexander Pamphilis
Very happy with the speed of the delivery. I installed these myself.
Where??? - 09/05/2018
Reviewer: Heather Marsh
Alarm seems great, but where do I put it??? Help please!!!
Customer Service Response:
Hey there, Heather. The NFPA recommends that homes should have smoke alarms installed inside every bedroom, outside of each sleeping area and on every level of your home, basement included.
Reviewer: Robert Murphy
Item still not received since ordering 2 weeks ago???
Customer Service Response:
Thank you for contacting us, Robert. A customer service representative will be contacting you shortly. They will provide answers to all of your shipping inquiries.
Replacement ionization - 08/25/2018
Reviewer: Greg Bloskey
Good dependable units. I've had twelve BRK alarms interconnected across my property for 20 years now
Reviewer: Samuel Alberti
This my second First Alert smoke alarm systems. I use 4 for my house , very to reinstall . Never had a problem with my other expired units. I highly recommend First Alert.
Very good - 08/06/2018
Reviewer: Vincent Casolaro
Came back to buy a bunch more.
Great price for a solid alarm - 08/03/2018
Reviewer: Mark Zuc
Had these delivered within days and installed within minutes. Had my original First Alert smoke alarms for 10 years so it was time to replace them, these worked perfect, very happy!