Material: Speaker box terminal cup made of plastic, copper and gold-plated metal. | Packing: Included 5pcs speaker box double loaded jacks binding post terminal cup. | Size: Exterior diameter 3"(75mm); Wall screw hole distance 1.77"(44mm). | Easy use: Rear connections use quick disconnect connectors, positive (Red) and negative (Black) indicators to ensure proper wiring. | After Sales Service: We also provide after sales service with our customers.