Polaris Active Bass Control Knob by Rockford Fosgate 2890427 1000 4

The Active Bass Control Knob by Rockford Fosgate is designed specifically for Polaris to enhance the bass output of your subwoofer. If you want more bass at lower volumes, simply turn the knob to your liking. As you increase the volume of the sound system, the patented technology of the Active Bass Control Knob prevents the subwoofer from being overdriven.