The copper palm in bi-metallic lugs is produced to provide excellent electrical conductivity, with the purpose of facilitating efficient transfer of current between the aluminium cable (through the aluminium barrel) and copper bus bars or terminals. Industry leading suppliers detail the copper palm in bi-metallic lugs as being produced from high-purity copper, commonly a minimum purit... https://www.pioneerpowers.com/bimetallic-lugs-and-connectors.php