First Alert SMI100-AC 9120B 12-Pack Interconnected Smoke Alarms

Overview

Discover the redesigned BRK 9120 series from First Alert. This 12-pack of hardwired smoke alarms blends faster installation with smarter, more reliable performance. With a 120-volt AC supply and a 9-volt battery backup, these alarms stay vigilant even during power outages, helping you monitor every level and room with confidence.

The ionization sensor targets fast-flaming fires, and the 85-decibel alert provides clear, immediate notification. When one unit triggers, compatible alarms in the series sound together, offering a coordinated warning throughout the home.

Key benefits

• Easy installation with a gasketless base and universal mounting brackets for secure placement
• Interconnects up to 12 alarms and supports up to 6 compatible devices like bells or horns
• Ionization sensor detects fast-flaming fires, paired with an audible 85 dB alarm
• Battery backup ensures continuous monitoring during power outages
• Single test/silence button simplifies operation, with tamper-resistant mounting brackets

What’s included in the 12-pack

• 12 hardwired smoke alarms with battery backup
• 120-volt interconnect wiring and mounting hardware
• Dust cover to keep units clean during construction
• 10-year limited warranty for long-term reliability

Smart features for fewer nuisance alarms

Smart technology helps minimize unnecessary activations while preserving protection. The latching alarm indicator identifies which unit initiated the alarm, and power indicators show the triggering unit at a glance, helping you respond quickly and calmly.

Installation and maintenance

Designed for easy setup, the alarms feature gasketless bases and a mounting bracket that accommodates a wide rotation range for precise alignment. A single test/silence control keeps operation straightforward, and tamper-resistant brackets help secure the installation.

Reliability and warranty

Built by First Alert, a trusted name in home safety since 1958, these BRK 9120 series alarms are designed for years of virtually maintenance-free service. A 10-year limited warranty provides added peace of mind.