Variable low-pass filter (40-250 Hz, 12 dB/octave) on subwoofer channel. Variable bass boost (0-18 dB at 45 Hz) on subwoofer channel. 4-gauge power and ground leads recommended - wiring and hardware not included with amplifier. Dimensions: 14-1/8"W x 2-1/16"H x 8-15/16D.