1.220V doorbell push switch 2.Install outside wall,show room number,D.N.D, ... kinds-Input Voltage-220V Item : doorbell push switchThere are 2 Kinds1.Low voltage 12V doorbell switch :Match wih other system to use ... control case(Bedside control panel,Master control case,Energy saving switch,and so on).Input voltage is 12V.2.High voltage ... ,Please wait a moment.2. With doorbell button3. Blue background light