$22
I bought these and didn't realize they were the wrong fit for our house til it was too late to return to Amazon! About this item 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.