The First Alert BRK 7010B Hardwired Photoelectric Smoke Alarm is a 120V single- or multiple-station smoke alarm designed for residential home use as well as institutional locations such as hospitals dormitories and multiple-family dwellings. This alarm is interconnectable and can be installed and linked with up to 18 compatible devices (up to 12 smoke alarms and 6 compatible devices such as bells horns and repeaters) so that when one triggers all alarms sound. It features a photoelectric smoke sensor designed to reduce false alarms from cooking smoke or shower steam while remaining sensitive to real danger and Optipath 360 technology provides 360 degrees of access to the alarm. The alarm uses a loud 85-decibel siren includes an integrated 9V battery backup in case of power outages and features a single button to silence false alarms and test the unit.