Features: 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/out connections for easy installation, allowing you to adjust Gains and frequency without the need for additional wiringperfect 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. Specifications: Material: plastic Head size: about 6x4cm/2.4x1.6inch Cable length: 5m Note: Please allow 1 to 3cm error due to manual measurement, please make sure you do not mind before you bid, Due to the difference between different monitors, the picture may not reflect the actual color of the item. Package includes: 1xCar Amplifier Gains Adjuster