High Performance 4mm Banana plug, silver plated, set-screw or soldered connections. Contacts designed to increase contact area and effect stable more transmission. Solid main body ensures very firm wire connections. Banana Conductor-Phosphor Bronze / Housing-Brass Max. Can receive wire from 4mm diameters up to 6.45mm. Banana Conductor 4.5mm X 16mm, overall length 40mm.