Smoke Detector with (490-0466) Battery Faxback Doc. # 15981 Silence Control The smoke detector is powered by one 9 Volt carbon-zinc battery. The battery should last for at least one year under normal operating conditions. The smoke detector has a low battery indicator, an audible "beep." It will operate at 30-40 second intervals for a minimum of 7 days. When this indication occurs, replace the battery with an Alkaline type (Radio Shack Cat. No. 23-553, Eveready Energizer #522, Duracell #MN1604) or Carbon-Zinc type (Gold Peak #1604P). (ALL-07/19/95)