QED Reference Digital Audio 40 is the new standard for digital coaxial S/PDIF signals benefiting from over 40 years of award winning expertise. It utilises a carefully engineered geometry to achieve the precise characteristic impedance required for the maximum transfer of S/PDIF signals. Silver plated conductors deliver a low resistance path for high frequencies and QED Digiloc plugs more closely match the cables characteristic  impedance reducing return loss by up to 1dB when compared to conventional RCA plugs. This ensures optimal signal transfer and improved micro-timing of the audio signal.