JAMHER Universal Car Amplifier Level Control Knob Sub Amp Volume Control Cable Specification: Color:Black Size(LWH):2.2*2.0*1.0 inch Input and Output:3.5MM JACK Cable length: 5M / 16.5FT Remote amplifier level controller Stereo RCA input and output Adds subwoofer level controls to any head unit It is very handy to adjust the subwoofer level without having to go into the menus in stereo Easy to install: The compact housing allows the car bass controller to be mounted virtually anywhere. Universal level controller allows for easy amplifier system control while driving. You can DIY mount the knob on your dashboard with the screws, also you can mounted in glove box and hidden out of the way. Universal RCA level controller made of premium material for durable and practical. Installing this knob, you can control the volume of bass with a turn of the knob instead of going through the radio every time. Great and helpful accessory for your car.