VICTRON GALVANIC ISOLATOR VDI-32 A
A galvanic insulator against electrolytic corrosion caused by shore power, among other things. It blocks low-voltage direct currents that enter your boat via the ground cable of the shore power supply.
The galvanic isolator consists internally of two diodes connected in antiparallel. In this way, the diodes allow current to flow in both directions, but only above a certain threshold voltage.