... 1M 3.Sensor Type: CO: electrochemical , Smoke: photoelectric, heat:temperatur combined detector3 in 1 co detector GS590Power Supply: DC 9V battery operatedSensitivity Setting ... , Smoke: photoelectric, heat:temperature sensorBattery spec: DC 9V,Carbon Zinc 6F22 or Alkaline 6Lr61, 1604A for ANSI,6AM6 for JIS6AM6 for JIS. Alarm sound ...