First Alert SA9120BPCN Hardwired Smoke Detector with Battery Backup

First Alert Replacement Hardwired Smoke Alarm (Model SA9120B) is 120V AC powered alarm with 9V battery backup in the event of power failure. The alarm can be interconnected with up to 12 other compatible smoke alarms and six compatible devices such as bells and horns. Features a universal mounting bracket and tamper-proof locking pins, plus adapter plugs to replace other non-First Alert alarms without rewiring. Alarm includes a loud, 85dB siren and single button test/silence. FeaturesFirst Alert Replacement Hardwired Smoke Alarm (Model SA9120B) is 120V AC powered alarm with 9V battery backup in the event of power failure. The alarm can be interconnected with up to 12 other compatible smoke alarms and six compatible devices such as bells and horns. Features a universal mounting bracket and tamper-proof locking pins, plus adapter plugs to replace other non-First Alert alarms without rewiring. Alarm includes a loud, 85dB siren and single button test/silence.