The E218sw is a high-performance direct radiation subwoofer with two, 800W, 18-inch, aluminum frame woofers. It's designed to produce crushing low-end for live performance with kick-drum and bass in the PA or for high-level, high-energy dance music. For portable applications it includes attachment points for four optional casters. The subwoofer's 4-ohm impedance means that a single cabinet can be optimally powered by a less expensive amplifier. The E Series is a range of passive loudspeakers offering robust construction, trusted reliability and overall sonic performance beyond expectations. Intended for sound reinforcement in entertainment applications including live performance, DJ and dance music, karaoke and event production, E Series loudspeakers will deliver outstanding results. Building on QSC's proven "Systems" methodology, the E Series loudspeakers' performance is further enhanced when paired with QSC's GXD or PLD amplifiers or with a QSC TouchMix digital mixer, and taking advantage of the on-board DSP and factory-tuned presets. These presets support a variety of applications including live sound reinforcement (with and without subwoofers), stage monitoring, dance music and karaoke.