Premium 4mm 24K Gold BANANA PLUGS Twin Screw Speaker Cable Connectors 4-Pairs(4 Red 4 Black) Material: Copper pin and plastic cover pure copper with 24K gold plating for maximum signal transfer and durability. Accept speaker wire:8AWG, 9AWG, 10AWG, 11AWG, 12AWG, 13AWG,14AWG, 15AWG, 16AWG, 17AWG, 18AWG, 19AWG, 20AWG Wire hole internal diameter: 4mm Total length: 47mm