Product review (5 stars): Worked better than expected
I purchased this unit, along with the extension rods, to clean the dryer vent at my house.  The house is about 5 years old and I was surprised how much lint had accumulated in the dryer vent.  I used this kit from the end of the vent inside the house only, as I do not have easy roof access.  I was surprised how well it worked, I started by carefully inserting the rods and counting/measuring them to see how long the duct was before attaching the brush or the drill.  I then marked the final section of rod with tape so I could slow down when approaching the rain cap from inside the house.  After attaching the brush and shop vac adapter, I followed the instructions carefully (especially the part about setting the drill clutch) and am very happy with the way it worked.  The vent is now clean and shiny inside, my dryer seems to take less time to dry clothes also.