For transmitting the optical digital audio signal, e.g. from a CD player to an amplifier, high-tech material for reliable signal transmission and optical fibre cable shielding, crystal Clear Material for very high data transfer rates, 24-karat hard gold-plated solid metal plugs, polished optical fibre tip for a snug channel stopper connection, dual protection, CCM-Crystal Clear Material, HRA-High Resolution Audio, 30 year warranty