Product review (5 stars): Awesome
OK this is awesome.  My house is 6 years old and I have never cleaned the dryer duct.  This tool was extremely easy to use and it removed a surprising amount of lint.  The length of my vent pipe is around 20 feet with several 90-degree bends and this handled it perfectly.  I ordered two of these to increase the length instead of ordering an extension pack.

Usage is simple = Just hook the rods together and duct tape the joints.  Use a drill CLOCKWISE and move the brush down the vent pipe.  I approached it from the outside of the house inwards. I ran the dryer on air dry while I ran the brush through and all the lint blew out.