Battery operated, ionization sensor smoke alarm. Features an easy to operate front load battery door, making replacing the battery simple and convenient. Unique battery compartment will not close if the battery is installed incorrectly. Locking feature on the back allows the battery door to lock if theft or tampering is a concern. Battery life varies according to use and application. Includes a Hush setting that temporarily silences nuisance alarms, adjustable mounting bracket for fast installation, and and easy to use test/reset button. Requires (1) 9-volt battery, included.