Kalevel 2pcs 2 Way Speaker Box Terminal Cup Square Connector Copper Speaker Binding Post Screw Down Terminal Banana Jack and Plugs Subwoofer Plugs DIY Home Speaker Kits Car Stereo Speakers (Black) Pack of 2pcs Speaker Box Terminal Cup Square Connector Material: durable plastic, copper and gold-plated metal. Speaker box terminal ensure a tight and secure connection. Overall diameter: about 80mm (3.2"); Cutout diameter: about 60mm (2.4");Top-mount depth: 20mm (0.8"). Rear connections use quick disconnect connectors. Positive (Red) and negative (Black) indicators to ensure proper wiring.