30cm subwoofer pre-loaded in bass-reflex tube enclosure (1300W). Pioneer TS-WX306T - 12" 30cm Bass Reflex Subwoofer with Tube Enclosure. The TS-WX306T tube houses a durable woofer that is built with a Voice Coil Cooling System (VCCS), improving heat removal from the centre of the subwoofer, thus increasing frequency response and high power handling.
eBay