Voice alarm can be programmed to tell type and location of danger if smoke or carbon monoxide is detected. Silence/test feature uses most remote controls to temporarily quiet unwanted alarms. Peak level memory recall stores and verbally communicates highest level of carbon monoxide detected. Pull out battery drawer for battery replacement. Low battery silence quiets low battery alert without affecting alarm operation. Loud 85-decibel alarm, low battery warning. End of life alarm chirps when it is time toreplace detector. 2 AA batteries included. UL listed. 5 year limited warranty.