The Kidde i9070 Smoke Alarm is an ionization, battery operated unit that provides users with an easy to operate front load battery door, making replacing the battery simple and convenient. The front load battery door allows users to change batteries without having to remove the smoke alarm from the mounting bracket. It's unique battery compartment design will not close if the battery is installed incorrectly, leaving you assured the batteries are properly installed. A locking feature, located on the back of the alarm allows the battery door to lock if there is a concern of theft or tampering. Along with its other premium features such as Hush, that silences nuisance alarms, this product was designed to help warn families from the dangers of smoke and fire hazards while providing its users with easy to use features to keep a maintained smoke alarm with working battery.