SMART VOICE 2-in-One SMOKE/CARBON MONOXIDE DETECTOR -Unused, still in original packaging -Ionization sensor technology senses fire and detects CO gas -Easy installation, no wiring needed: operates on a 10-year lithium battery -Detects during power failure-Green LED indicates power to the smoke detector -85-Decibel Voice Alarm when smoke detector is sensing smoke or fire -Replacement Alert indicates when the smoke alarm needs to be replaced Test-Hush Button: Allows for easily testing and silence false alarms -Interconnectable With Up To 24 Devices-Complete User Guide Included With Instructions -UL Certified, 10-year limited manufacturer warranty