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 & QED Digiloc plugs more closely match the cables characteristic impedance reducing return loss by up to 1d B when compared to conventional RCA plugs. This ensures optimal signal transfer & enhanced micro-timing of the audio signal.