Auxiliary switches report the status of the main devices on which they are mounted. The HSH auxiliary contact block is suitable for hum-free contactors of the HS 2 and HS 3 series. It has a normally open contact and an normally closed contact. Areas of application: These devices are suitable for querying the operating status of power supplies in residential and commercial buildings as well as industrial plants. Notes: The auxiliary switch does not affect the function of the base device.