I purchased a pair of these smoke detectors to replace some old, hard-wired units that came with my house. They are linked together so that if one goes off, the other one will as well. Installation was a snap and the battery backup is a welcome feature. You can get a pair on Amazon for about $20.
Additional features include:
- Red LED flashes until reset for quick, clear identification of initiating smoke alarm in interconnected system
- Visible low battery indicator helps locate chirping unit
- Front loading battery door makes battery changing simple, power link tab makes installation faster
- False alarm control quiets unwanted alarms for up to 8 minutes
- Interconnects with other compatible Firex smoke alarms and heat alarms