There is nothing worse in car audio world than the magic blue smoke caused by voltage drop. That's why it is critical & necessary to monitor your car audio amplifier voltage to prevent damage to all your car audio equipment. Installing a separate voltmeter, separate power switch and a separate bass knob can prevent all those which can be of great hassle. Combining all those three issues, Recoil represents the solution with our universal bass knob with digital voltmeter. This unit offers remote gain control, a rotary pushable on-off switch and a digital voltmeter display.