The First Alert SMICO100-AC hardwired smoke and carbon monoxide detector offers reliable protection against smoke and carbon monoxide. Featuring superior functionality, the hardwired Interconnect smoke detector with a 9V Battery Backup meets new industry standards. It can operate independently or be interconnected with other compatible detectors to create a comprehensive home alarm system for early warning in emergencies. When one wired smoke and carbon monoxide detector sounds, all connected alarms will activate, providing a timely alert for fire or carbon monoxide threats. You can integrate this smoke alarm with up to 12 other First Alert or BRK detectors and 6 additional compatible devices. Please consult the user's manual for a list of compatible alarms. If the interconnected alarm system is triggered, the latching alarm indicator will visually identify which unit initiated the alert. The hardwired quick-connect plug allows for easy installation and replacement of existing hardwired detectors without the need to rewire your home's electrical system. The SMICOCO100-AC Interconnect smoke detectors are designed for hardwired installation, but with their 9V battery backup, they ensure continuous protection even during power outages. An optional locking feature helps prevent unauthorized removal of the alarm. Use the test/silence button to test the detector regularly to check that it is working properly and silence false alarms. Detectors don't last forever; the end-of-life warning will indicate when it's time to replace the alarm. See the user's manual for how and when to test and replace alarms.