JL Audio RBC-1 Remote Bass Control.

The RBC-1 remotely controls the Bass Level of the following JL Audio amplifiers:
JD-Series: JD250/1, JD500/1, JD1000/1
JX-Series: JX250/1, JX250/1D, JX500/1, JX500/1D, JX1000/1D
HX-Series: HX300/1 in Low Pass Mode (Note: M-RBC-1 is also available)
MHX-Series: MHX300/1 in Low Pass Mode (Note: M-RBC-1 is also available)
MX-Series: MX300/1, MX500/1 in Low Pass Mode (Note: M-RBC-1 is also available)
RD-Series: RD500/1, RD1000/1, RD1500/1, RD900/5 When the RBC-1 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. The RBC-1 remotely controls the Bass Level of the following JL Audio subwoofer systems:
PowerWedge+: All Models
MicroSub+: All Models When the RBC-1 is connected to the above subwoofer systems, 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.