Kenwood XR1001-1 Reference Fit Mono Power Amplifier with 1000W x 1 output at 2 ohms, 2000W maximum power, Bass Knob Included, Speaker level Inputs and Signal Sensing Turn On - Creative Audio
Kenwood KCA-WR10 Wired remote bass boost at Crutchfield
Kenwood Xr901-5 Reference Fit 5 Channel Power Amplifier W/ 75wx4 Output And 600w X 1 At 2 Ohms And 1800w Maximum Power, Bass Knob Included : Target
CT Sounds Universal Bass Knob - Digital Voltmeter, Blue LED Display, R – Green Bee Solutions
Kenwood KAC-7252 2-channel car amplifier 170 watts RMS x 2 at Crutchfield
PAC Line Level Controller (Bass Knob) – G2 Dynamics, LLC