The item is a 3pcs professional and practical 2-way speaker terminal round spring cup , which is mainly made of durable plastic and gold-plated metal, and designed for DIY speaker and subwoofer boxes. Gold-plated contacts for optimal signal transfer, and spring terminals a tight and secure connection. It is easy to install with screws locking and easy to use. 3 pieces of the speaker terminal round spring cup in one set will be sold together. Cutout diameter: about 45mm (1 7/8 inch); Overall diameter: about 75mm (3inch); Top-mount depth: 20mm (7/8inch). and high quality 2-Way Speaker Box Terminal Connector Binding Post Round Spring Cup Subwoofer Plug. Terminal cup for speaker & subwoofer boxes. Rear connections use quick disconnect . Positive (Red) and negative (Black) indicators to proper wiring. Suitable for 4mm banana plugs, spade terminals or wire. , and durable. Colour: as shown Material: plastic + metal Package Contents: 3 x 2-Way Speaker Box Terminal Binding 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.