The Captivator S1 is a sealed subwoofer with a 18″ driver and 2400 watt amplifier that has been digitally optimized to the smoothest frequency response and highest possible output with minimal distortions.
Home Theater Shack review:
http://www.hometheatershack.com/forums/speaker-subwoofer-reviews/128897-jtr-speakers-captivator-s1-review.html