M-Audio SBX Studiophile subwoofer. Superb subwoofer for music, cinema and studio monitoring alike!
Check the details and top reviews here http://www.zzounds.com/item--MDOSBX8
This is now discontinued but was £300-400 when new.
Works perfectly, there are very small screw holes on the side of casing (see picture) but these do not affect the sound.
Grab a bargain at only £95