This 15" powered subwoofer features a bottom-firing, flared port, bass reflex design for reduced port noise and increased bass response. It also utilizes a heavy-duty long-throw 15" woofer and up to 150 watts of power, with a frequency response of 23-140 Hz. The amplifier features high and low level inputs and high level outputs, a phase switch, independent volume control, an auto on/off switch (activated by an input signal), a variable 12 dB electronic low pass filter and crossover frequency control. This subwoofer is 19.75" H x 19.25" W x 19.75" D and finished in a black vinyl.