First Alert BRK SC9120B-6 Hardwired Smoke and Carbon Monoxide Detector (CO) with Battery Backup. 6-Pack , WhiteThe First Alert BRK sc-9120b hardwired combination smoke and carbon monoxide alarm uses electrochemical Co sensing technology and ionization sensor for smoke detection. This hardwired dual Co smoke alarm can be connected to other compatible BRK or First Alert hardwired Co smoke detectors within a single-family residence. The latching alarm indicator automatically identifies which unit initiated the alarm-even after the conditions that set off the alarm have subsided. Using a 9-volt backup battery, the smoke and carbon monoxide detector can function even in the event of a power outage. Additionally, the Co smoke alarm features a single test and silence button, as well as indicator lights that let you know whether the danger is smoke or carbon monoxide. The tamper-resistant locking brackets and universal mounting brackets make installation easy. Faster turnarounds on job sites with the easy-to-install, most-trusted alarms in home safety..First Alert 9120B Hardwired Smoke Detector Alarm, 1-Pack, WhitePromote greater household safety with the First Alert 9120B Hardwired Smoke Alarm with Battery Backup. This 120 volt AC smoke detector uses an ionization smoke sensor to reliably detect smoke from hot, fast flaming fires and alerts you with a loud 85 decibel alarm. Designed to be wired directly into your home's electrical system, this hardwired smoke detector features a backup battery that helps keep the alarm functioning even in the event of a power outage. The gasket less mount helps ensure a perfect alignment for easy installation, while tamper resistant locking pins keep the alarm secure. And thanks to the convenient test/silence button, you can easily check whether the alarm is functioning properly and mute false alarms. This smoke alarm can integrate with up to 12 other First Alert or BRK hardwired alarms and features a latching indicator that identifies which unit triggered the alarm.The revolutionary BRK 9120 series smoke alarms have been redesigned from the ground up. They install faster, perform better, and are even smarter than before. All of these improvements help reduce nuisance alarms and save time and money. BRK Electronics’ smoke alarms are designed to be easy to install, easy to maintain, and quality-engineered for years of virtually maintenance-free service. The 9120B includes an ionization sensor which helps detect fast flaming fires that consume combustible materials rapidly and is 120-volt AC inter-connectable (with maximum 18 compatible devices), which lets the alarm be interconnected with up to 12 other compatible smoke alarms and six compatible devices like bells, horns, repeaters, and door closers. If one unit triggers an alarm, all smoke alarms in the series will sound. Power indicators show which unit in the series initiated the alarm and a latching alarm indicator automatically identifies which unit initiated the alarm. This is smart technology to reduce nuisance alarms. It also has a 9-volt battery backup for peace of mind during power malfunction, a single test/silence button which both silences a non-threatening alarm or low battery warning and allows you to test the unit's functionality, a perfect mount system, including a gasket less base for easy installation and new mounting bracket that keeps the alarm secure over a wide rotation range to allow for perfect alignment, and a mounting bracket lock for tamper resistance. A dust cover keeps the unit clean during construction. It comes with a 10-year limited warranty.