It's a Definitive Technology 12" sub with it's own amp. Back of the sub says "Powerfield 12 Subwoofer" Baltimore, MD
I bought it at a thrift store for $20 and am thinking about getting rid of it now that I got my shiny new (to me) pair of RTA's. I just don't have the room.
I can't find any information about this thing though and have no idea what is a reasonable price to ask or if it's only worth throwing in the garbage.