Product review (5 stars): Works VERY well.
This thing worked AMAZING.  I got a TON of lint out of my vent piping.  Dryer works better now and runs cooler.  Drying times have been reduced and I feel safer now (lint fires).  I was amazed at how much lint build up there was.  I worked from the outside in towards the dryer a little at a time, with the dryer running (blowing out) on cool/air only.  Then I went inside and and slide the dryer away and worked from the inside out.  I used a leaf blower to push the lint out from this direction.  By working from both directions I didn't need to purchase extension rods.