The M-RBC-1 controls the Bass Level and features a water resistant connection cover designed for use with the following JL Audio amplifiers: MHX-Series: MHX300/1 (in Low Pass Mode) The M-RBC-1 rotary control is IPX6 water-resistant (splash-proof, not submersible) and includes a black ABS knob, mounting hardware and one 16.4 ft (5 m) cable.