Insulated post, external parts insulated Easy installation with screws locking and easy to use Gold plated to protect against corrosion and to the highest quality audio with no distortion Product Name: Banana Plug Connector Jack Socket Binding Post Full Length: About 33mm Connector Processing: Gold Plated Max Outer Diameter: About 14.5mm Wire Hole Diameter: About 4mm Outer Diameter Of Screw: About 7mm Screw Shaft Length: About 12mm Screw Shaft Diameter: About 4mm Insulator Outer Diameter: About 6.6mm Recommended Case Opening: About 6.8mm Color: gold+red+black Material: copper Package Contents: 10 x binding posts (5 red and 5 black) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.