Makes quick work of holes in difficult to machine or hard materials, or slots with tiny end mills.  It wont make a jig grinder out of your 1938 Bridgeport, but it has its uses.  Its about the only way to turn a 

carbide cutter smaller than 3/32 fast enough.  Comes with 2 shanks and 3 collets, air line hookup, spare wheels and some wrenches.