24k gold plated and copper made, non-magnetic. Converts amplifiers with screw type terminals to use standard banana plugs or bare cable. Dimensions of Spade: inner width: 6mm; outer width 8mm; depth:10mm. For old style speakers and Accept different types of banana plugs. Also can be used for speaker spade to banana socket adapter. Accept cable diameter: 6mm Specially made for McIntosh, Marantz, Dynaco ST70, HeathKit, Eico, Fisher and any other vintage amplifiers. Top quality.