Eaton Crouse-Hinds series MTL7700 Zener barrier, 10-35 Vdc, Up to 35mA, 2 channels, Polycarb, DIN rail, Up to 50mA, supply >28V or low load resistance, BskuPage.MTL7707Puilt-in overvolt protection, For switch inputs and outputs, 2W transmitters (IIB gases)