Designed to help promote household safety, the First Alert hardwired smoke alarm with battery backup can provide early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials. To facilitate hassle-free installation, this fire and smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the detector secure over a wide rotation range while maintaining perfect alignment. The ionization fire 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. 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 smoke and fire detector 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 hardwired alarm.
Designed to help promote household safety, the First Alert hardwired smoke alarm with battery backup can provide early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials. To facilitate hassle-free installation, this fire and smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the detector secure over a wide rotation range while maintaining perfect alignment. The ionization fire 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. 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 smoke and fire detector 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 hardwired alarm.
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The lowest price for First Alert 9120B / SMI100-AC Smoke Detector Hardwired Alarm with Battery Backup 6-Pack right now is $264.00 at desertcart.com.au.
The all-time low was $264.00 on 4 Nov 2026. That's the lowest price we've ever tracked — a great time to buy.
Prices last updated 4 Nov 2026.
First Alert 9120B / SMI100-AC Smoke Detector Hardwired Alarm with Battery Backup 6-Pack
Designed to help promote household safety, the First Alert hardwired smoke alarm with battery backup can provide early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials. To facilitate hassle-free installation, this fire and smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the detector secure over a wide rotation range while maintaining perfect alignment. The ionization fire 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. 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 smoke and fire detector 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 hardwired alarm.
Designed to help promote household safety, the First Alert hardwired smoke alarm with battery backup can provide early warning of fire. This hardwired smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast-flaming fires. The sensor is optimized to detect flaming fires, such as those caused by paper, kitchen grease, and other fast-combusting materials. To facilitate hassle-free installation, this fire and smoke alarm features a streamlined mounting system with a gasket-less base. The mounting bracket keeps the detector secure over a wide rotation range while maintaining perfect alignment. The ionization fire 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. 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 smoke and fire detector 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 hardwired alarm.
Last updated at 04/11/2026 11:17:58
First Alert BRK SMI100-AC Hardwired Smoke Detector with Battery Backup, 6-Pack
Delivery between 10–13 Nov $29
| Detected Substances | Smoke |
| Sensor Type | Ionization |
| Detection Method | Ionization |
| Detection Range | Coverage of larger spaces |
| Certifications | UL standards |
First Alert BRK SMI100-AC Hardwired Smoke Detector with Battery Backup, 6-Pack
Delivery between 10–13 Nov $29
| Detected Substances | Smoke |
| Sensor Type | Ionization |
| Detection Method | Ionization |
| Detection Range | Coverage of larger spaces |
| Certifications | UL standards |
