... 3.Sensor Type: CO: electrochemical , Smoke: photoelectric, Heat:temperatur combined detector3 in 1 co detector GS590Power Supply: DC 9V battery operatedSensitivity Setting ... , 25-85%R.H.Sensor Type: CO: electrochemical , Smoke: photoelectric, heat:temperature sensorBattery spec: DC 9V,Carbon Zinc 6F22 or Alkaline ...