First Alert knows smoke detectors aren’t exciting—until they’re the only thing standing between you and a house fire. The 9120B is a hardwired unit with a 9-volt battery backup, so it keeps working when the power goes out. That matters more than you think. Most home fires happen at night, and power outages are common during storms. This detector covers that gap.

The ionization sensor is tuned for fast, flaming fires—the kind that spread in minutes. At 85 decibels, the alarm is loud enough to wake you from deep sleep. The test and silence button is straightforward: one press checks the circuitry, and if you burn toast, it kills the false alarm without yanking the unit off the ceiling. The latching indicator lights up on the specific detector that triggered the alarm, so you don’t have to guess which room started it.

Six units cover a typical three-bedroom house with spares for hallways and basement. The hardwired install requires basic wiring knowledge or an electrician. Battery backup needs annual replacement. For $80 to $100, this pack delivers reliable, code-friendly protection without gimmicks. It’s not flashy. It’s just the thing that might save your life.