JBL EON 518S Portable 18-inch 500-Watt Self-Powered Subwoofer Latest JBL 18 inch Differential Drive woofer technology for superb bass anywhere Class D Power amp delivers superb bass at Almost half the weight of the competition - no more sore backs! Balanced XLR inputs (stereo) with loop through to top speakers or use the simple 1/4 inch speaker level mono input