Fangrui Product Details 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 Wiring - For Audiophiles Seeking Sound Quality. Suitable For Music Enthusiasts And Professional Sound Producers Who Demand Convenient Control Over Their Cars 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/1.97x2.76inch Cable Length:5m Colour:black Material:plastic Package Contents: 1 * Car Amplifi