Technical Pro Powered Subwoofers are designed specifically for club and high-end pro audio users. The heart of the system is a massive driver of 15" ideal for the most demanding environments where pure bass power is the goal. They produce amazing new levels of bone-jarring bass, making Technical Pro Subwoofers a superior choice for anyone looking for thunderous lows in large venue environments. The XTREME subwoofers have a built-in amplifier putting all of this power into one convenience box. Moreover, their powered speaker outputs and power up to two more speakers. The switchable high pass crossover allows for the satellite speakers to provide the mids and highs to complement the bass of the XTREME.