Quality Material: Tough, durable, anti-corrosive ABS plastic mounting plate for long service time; Metal contacts for optimal signal fer Spring Terminal Design for a quick, tight and secure connection. Simply press down the terminals and insert speaker wire for direct contact. Clear Sign: Red (Positive) and Black (Negative) indicates polarity on binding post, (+) and (-) are clearly marked on the front and the rear to ensure proper wiring Easy Installation: The speaker box terminal cup is usually installed on the back of the speaker shell, which has 4 mounting holes for easy installation. Please check the size before ordering Wide Application: designed for DIY applications, suitable for subwoofer box, small speaker, surrounding box, center box, small bookshelf box, etc Colour:Black Material:ABS Package Contents: 4x Speaker Box Terminal Cup 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.