Quality Material: Tough, durable anti-ABS plastic mounting plate for long service life; metal contacts for optimal signal transfer Spring Terminal Design allows for a quick, tight, and secure connection. Simply press down the terminals and insert speaker wire for direct contact Clear Polarity Sign: Red (Positive) and Black (Negative) indicate polarity on binding post; (+) and (-) markings are clearly displayed on both front and rear for correct wiring Easy Installation: Speaker box terminal cup is typically installed on the back of the speaker shell, featuring 4 mounting holes for simple setup. Please verify dimensions before purchase Wide Application: Suitable for DIY projects, including subwoofer boxes, small speakers, surround sound enclosures, center channels, and bookshelf speakers Color: Black Material: ABS Package Contents: 4 x Speaker Box Terminal Cup Note: Light reflection and differences in display screens may cause slight variations between the color of the item in the image and the actual product. Measurement may vary by +/- 1-3 cm