Acoustic Audio RWSUB-15 Down Firing Powered Subwoofer, 15-inch,(Black) Acoustic Audio Specialty Series home theater powered subwoofer, 600 watts peak power, frequency response is 21Hz-250Hz, efficiency is 98dB, 8ohm impedance Built in digital drive high efficiency amplifier, 15&rdquo; down firing long throw subwoofer, high rigidity poly zirconium cone, adjustable independent gain control Low level and speaker level inputs and outputs, variable low pass frequency crossover control, signal sensing auto shut off function, phase control switch, bottom slotted bass port Black ash high density MDF enclosure with advanced RFL bass reflex design, product dimensions (H x W x D) 14.6" &times; 16.5" &times; 18.5", designed and engineered in the USA Use for in wall or in ceiling home entertainment, home theater systems, surround sound systems and multiple room systems