First Alert 9120LBL Smoke Alarm provides reliable fire detection for your home or business. This hardwired smoke detector features ionization sensing technology to quickly identify fast-flaming fires. With a 9V battery backup, it continues protecting your property even during power outages. The alarm produces a loud 85-decibel alert to wake occupants and alert nearby areas. Easy to install on standard electrical boxes, this UL-listed detector meets safety codes and standards. Keep your family and valuables safer with dependable smoke detection coverage.