The JBL EON518S Portable Self-Powered 18" Subwoofer is a great compliment to the EON500 series, and gives you an easy way to give your show a bit more power. The EON518S is an 18-inch, direct radiating, high performance powered compact subwoofer system. Designed to extend low frequency performance of any EON system. It also offers the convenience of an integrated crossover and stereo loop-thru capability. The EON518S is comprised of a 460 mm (18 inch) Differential DriveÂ® woofer driven by a 500 watt Class-D digital amplifier.