1000W 2-way 15-inch active PA speaker system with MP3 player, aluminum-diaphragm compression driver, ultra wide dispersion and large format exponential horn. Additional Line output allows linking of additional speaker systems. Versatile trapezoidal enclosure design allows different positioning such as stand mounting with 35mm pole socket, tilts on its side for use as floor monitor. 8-button user interface and high-contrast, multi-function LCD panel let you instantly browse tracks and enable shuffle, repeat or single-play modes. 15-inch woofer has about 40% more surface area with which to move air than 12-inch and that translates into more bass. So if you're addressing a small meeting or jamming at the coffee house, B112MP3 might be all you'll ever need. But if you're providing disco in busy nightclub, hosting Karaoke night in your living room or just need to crank it up louder, then B115MP3 is a better choice.