Usage Tips:Suitable for 4pin line,12v power amplifier equipment. Enhances your Auto Sound experience with this Bass Knob, General car amplifier Volumes control designed for precise bass and Volumes adjustments. This knob features simple in or out connections for easy installation, allowing you to adjust Gains and frequency without the need for additional wiring - perfect for audiophiles seeking best sound quality. Suitable for music enthusiasts and professional sound producers who demand convenient control over their car's Sound while on the move. Whether cruising on a long road trip or enjoying your favorite tracks during daily commutes, this bass knob ensures your Sound is tailored to your preferences. This Bass Knob not only complements modern auto interiors with its design but also offer a and responsive interface for fast Sound adjustments, making it essential accessory for any Auto Sound upgrades. Head size:about 5x7cm or 1.97x2.76inch Cable length:5m Colour:Black Material:Plastic Package Contents: 1 x Car Amplifier Volume Control Cable 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.