First Alert BRK 9120B/SMI100-AC Smoke Detector – Hardwired with Battery Backup (3-Pack)

Overview

The First Alert BRK 9120B/SMI100-AC is a hardwired smoke detector designed for reliable, round-the-clock protection. It operates on standard 120-volt AC power and includes a built-in 9-volt battery backup to maintain alerting during power outages. An ionization sensor targets smoke from fast-flaming fires, delivering a loud 85 dB alarm to prompt quick awareness throughout the home.

Sold as a 3-pack, this model offers practical coverage for essential living areas. The unit emphasizes straightforward maintenance with tamper-resistant locking pins and a single-button silence/test function, enabling quick checks without compromising safety. The combination of continuous power and backup energy helps ensure that alerts remain active when you need them most, even in challenging conditions.

Key benefits and real-world use

In everyday settings, early warning can make a meaningful difference. Hallways, bedrooms, and living spaces benefit from a reliable alert that travels through doors and into adjacent rooms. The loud alarm is designed to be heard clearly, helping occupants respond promptly. While no device can guarantee prevention of fire damage, having a dependable detector increases situational awareness in critical moments.

• 120-volt AC power with included 9-volt battery backup for continuous operation
• Ionization sensing tuned for fast-flaming fires
• Tamper-resistant locking pins and a simple single-button silence/test control
• 3-pack so you can outfit multiple rooms for broad coverage

Installation, testing, and maintenance tips

For a smooth setup, start with power off and verify wiring polarity. Ensure all wire-nut connections are secure before mounting. After installation, use the built-in silence/test button to confirm the audible alert is functioning as expected. Regular checks help keep the system performing as intended.

• Check wiring polarity (hot/neutral) and secure all wire nuts
• Test the alarm after installation using the silence/test button
• Conduct routine maintenance as part of your home safety checks

Why choose this First Alert model

This detector combines a straightforward, reliable hardwired setup with a backup power option, reducing the risk of silent alarms during outages. The 3-pack offers practical scalability for multi-room protection, while the compact, tamper-resistant design supports easy mounting in common traffic areas. It’s a balance of practical safety features and user-friendly operation that can fit into many home layouts without complicating maintenance.