Product review (5 stars): Perfectly clean vent now!
My, oh my! So easy! I got this and one extension kit (extra 12') and followed the simple directions. Keep the drill running clockwise and all will be well. The adapter to the shop vac was set up by the end of the vent by the dryer and I ran the brush from the outside of the house, although you could do it several different ways. Start to finish was less than a half hour and it took 23' of extensions. It also easily navigated the 5 elbows in the run.  Only change I would make would be to hook the shop vac up outside, since there was some fine dust kicked out of the vac which (my wife said) necessitated a cleaning of the room. Might have been a sneaky ploy, but it did work. As for the product, no hesitation at all in recommending it!