The SB528z is a high output, large-format subwoofer system. This versatile, all-purpose subwoofer is designed for permanent installation where the fatter-sounding output of dual 18 inch drivers is desired. The SB528z works well with most full-range loudspeakers in a variety of applications including: large houses of worship, large auditoriums/theaters, f/x reinforcement, cinemas, and large dance clubs. Two iterations of this product exist: