http://www.drgas.com/street-cat.html
 Ball and cone joints can be used in almost any location in the exhaust
 system. These are great to install near the mufflers in conjunction with
 headers. They make removal of the exhaust system for service needs a snap.
 They are self aligning and gasketless. 2 ¼", 2 ½" and 3" sizes are
 available. The 2 ¼" and 2 ½" sizes can be joined for a step in tube size
 at the joint.

 Priced in pairs.
 2 ¼" to 2 ½" 	$42.95
 2 ½" to 2 ½" 	$42.95
 3" to 3" 	$59.95


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I didn't see the original post, but you can also find the ball joint
components 
in any parts store, if you know where to have them look. This stuff is part
of  
the "accessory pack" for some universal fit cats. My local jobber/WD has        
catalogues with tons of the things and they are 1/3 the cost of the ones on
the 
web site. No way of knowing about the quality of either untill you have
them in 
hand, though. I expect they are the same stuff.