First Alert Smoke Detector Alarm | Hardwired with Backup Battery, 6-Pack, BRK 9120B6CP Note : A loose neutral (white wire) connection within the home junction box could prompt a device malfunction. Equipped with an ionization sensor, this smoke alarm reliably detects smoke from fast-flaming fires and alerts you with an 85-decibel alarm To ensure complete protection make sure to place one on each level of your home and in each bedroom Can connect to other compatible BRK or First Alert smoke detectors, to ensure all alarms will sound when smoke is detected Simple to use, with a single test/silence button, and side-load battery compartment; tamper-resistant locking brackets and universal mounting brackets make installation easy Rigorously tested to meet UL standards Keep your family safe with this 6-pack of hardwired smoke alarms; the battery backup means constant monitoring, even if there's a power failure