The conductivity of the aluminum barrel in bi-metallic lugs is usually defined as a minimum percentage of the International Annealed Copper Standard (IACS). Most manufacturers, including top suppliers like Pioneer Power International, make sure that the aluminum used in these lugs meets or even surpasses 61.8% IACS conductivity for the aluminum barrel. While some product lines might s... https://www.pioneerpowers.com/bimetallic-lugs-and-connectors.php