Siemens sirius 3rt19 contactor and 3rh19 din rail control relay siemens 3rt1916 1bb00 the siemens sirius surge suppressor varistor 3rt1916 1bb00 is supplied without led the s00 size varistor is for plugging onto the front side of the contactor with or without an auxiliary switch block the varistor has a dual voltage of 24 to 48v ac and 24 to 70v dc siemens 3rt1916 1bb00 varistor s00