AudioQuest SureGrip 300 Multi-Size Spade - (Set of 4) Gold Fits up to 9 AWG speaker cables. Fits 1/4  5/16 binding post. Cold-Weld System for an ideal connection, better sounding than solder: Tighten Allen-screws with supplied tool to create an ideal connection between plug and conductor, then slide the no-magnetic-interference ABS casing over the banana screw into place. Pure Hanging Gold plating directly over Purple Copperno sound-damaging in-between nickel. High-Purity Purple Copper provides cleaner and clearer sound compared to lesser coppers or brass used in other premium connectors.