The First Alert SMICO105-AC hardwired smoke and carbon monoxide detector offers reliable 2-in-1 protection against both smoke and carbon monoxide. Featuring superior functionality, the hardwired Interconnect combo smoke and co2 detector with a 10-year 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 and carbon monoxide detector 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 SMICO105-AC Interconnect Combination smoke and co2 detector combo is designed for hardwired installation but with its 10-year battery backup, it ensures continuous protection even during power outages. An optional locking feature helps prevent unauthorized removal of the alarm. For easy maintenance, the 10-year backup battery eliminates the need for battery replacements for a decade. Use the test/silence button to test the combination 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.