Hifonics HFEQ is a 4-band EQ, 2-way crossover, and line driver that provides filtered signals to front and rear amplifiers and subwoofer output using a single pair of inputs. It features two-color (red/blue) control knob backlighting, unbalanced line input, subwoofer unbalanced output, subwoofer crossover frequency control, input level control adjustment, mono/stereo selection, fader control, mounting hardware, and various controls for adjusting bass, midrange, and treble. It also has a subwoofer output level control and a remote gain control module.