This ended up doing what I wanted but not as slickly as I hoped for.  The description didn't give me a complete picture of how this would work.  I had hoped it would slip over or into the 4" exhaust on my bandsaw, it didn't.  It also is 4" so I cut it down to about 3/4" lenghth and duct taped it to the bandsaw.  My 2 1/2" shopvac hose fits perfectly on the other end.  I'm happy with this arrangment since it kept the price down for the modification.