The mounting hole in the copper palm of bi-metallic lugs plays a vital role in creating a secure and dependable connection between the aluminum cable and the copper busbar or terminal. This copper palm is crafted with one or more holes—whether it’s a single, double, or even four holes—allowing the lug to be bolted or screwed directly onto the surface of the copper busbar or terminal. ... https://www.pioneerpowers.com/bimetallic-lugs-and-connectors.php