Process of surface treatments include gold plating, silver plating ,nickel plating, chrome plating, tin plating, zinc plating, electrostatic painting, cataphoretic coating, aluminium oxidizing, etc.
The connectors are gold plated and of bi-wiring type so that you can connect to the amplifier with double cables (bi-wiring), or connect to two amplifiers (bi-amping) to further improving the sound.