The 10D390K with Varistors 31V 77V 500A Through Hole RoHS is an electronic component manufactured by Ruilongyuan. It is a flame-retardant, bidirectional device that provides electrical protection against transients such as electrostatic discharge, inductive switching, and lighting surges. It has a RoHS compliant through-hole mounting configuration and works within a voltage range of 31V to 77V and a maximum current rating of 500A. This component is designed for use in a range of electric power and modeling applications.