The item is a set of 3pcs professional and practical 2-way speaker terminal round spring cup connectors, 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 connectors 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 connectors. Positive (Red) and negative (Black) indicators to proper wiring. Suitable for 4mm banana plugs, spade terminals or bare wire. Compact, reliable 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.