This 12-pack of First Alert BRK SC7010B Hardwired Smoke and Carbon Monoxide Alarms includes battery backups so that they keep monitoring safety even if there’s a power failure. They're designed for residential use as well as for institutional locations such as hospitals, hotels, dorms, and multiple-family dwellings. This alarm is Interconnectable and can be linked with up to 18 compatible devices (up to 12 smoke alarms and 6 compatible devices like bells, horns, and repeaters) so that when one triggers, all alarms sound. This alarm emits a loud, spread-spectrum 85-decibel alarm designed to be heard even by those with some hearing issues. In addition to electrochemical CO-sensing technology, the detector also features a photoelectric smoke sensor that can help detect slow smoldering fires. One button silences any nuisance alarms, and also tests detector functions, while lights indicate if the alarm detects smoke or carbon monoxide. The latching alarm indicator automatically identifies which unit initiated the alarm, even after the conditions that set off the alarm have subsided. And an end-of-life signal enhances your safety by letting you know when it's time to replace the unit. Hook up to AC power with the “quick-connect" wiring harness for easy installation. Faster turnarounds on job sites with the easy-to-install, most-trusted alarms in home safety