The HD-RLC remotely controls the Bass Level of the following JL Audio amplifiers:
HD-Series: All models
XD-Series: All models
MHD-Series: All models
M-Series: All models
When the HD-RLC is connected to the above amplifiers, it acts as an attenuator on the input gain of the amplifier and is used to adjust the overall level of the amplifier from the front of the vehicle.
A satin-finish aluminum knob can be purchased separately.