Product review (4 stars): THIS CLEARED THE PLUGGED  VENT (Exactly what I needed)
SHORT STORY:  It worked, and solved the Dryer Problem.
WARNING:  If you think you can chuck up the rods & turn on the drill, then this product will fail, and it will not clear the vent for you.  IT MUST BE USED GENTLY / PATIENTLY!  I can only recommend this, if you understand how fragile the rods really are.
LONG STORY:  My Aunt's Dryer Quit Drying, & she wanted me to buy her another Dryer.  When I checked the Dryer out, I found that it was heating, tumbling, & blowing air.  I checked the vent, and found that it went up inside the wall, and vented through the roof.  After using a 'Leaf Blower' to see if I could blow a handful of dirt out the vent, my wife said she saw nothing when she watched the vent.  (There was a small piece of lint visible in the vent, and it never moved during this test.)  The roof was ceramic tile, and I didn't want to climb up on the roof, unless I absolutely had to.  I didn't know what I was going to do, and assured my Aunt that if I was right, even a new Dryer would not work until this vent was cleared.  I found this at the BOX STORE and being mechanically inclined, I could tell that the Concept of this device was Brilliant, but the quality, to make it reasonable to buy, was much less than I would have liked.  I had to be very careful, I used the drill to very slowly turn the rods, and stop immediately after 1-revolution, to allow the Rods to unwind, in case they had twisted while I was operating the drill (which it did throughout the process).  I had to very carefully gently apply the tools & drill twist force, and eventually cleared the plugged vent.  The Vacuum cleaner attachment cleared the vent as I extremely slowly cleared the plug.  I packed up the kit, and intend to clean the vent on an annual basis.  I used my iphone / camera in the vent opening, and could see up the pipe before (no visible light) & after (sunlight shone inside vent).
DISCLAIMER:  I needed this ASAP, and actually bought it at one of the "BOX STORE" or I would no doubt have gotten it from Amazon, as I usually do... (I buy from Amazon almost exclusively by product reviews, and wanted to write one for this product.)