This seems to be a very efficient woofer during testing.
I bought it on clearance for $4.97 and just found two more on Ebay.
With it's sensitivity and fairly large Xmax, I am thinking of using it as a low powered sub for a set of FR satellites.
I put one of these in a Decware Death BoxII and man! does this thing sound incredible!
While I do not believe there is such a thing as a "Universal Sub Box" the DBII comes darn close!
I have only tried it in cars but, once tuned, it delivers clear, deep and LOUD bass.