Product review (5 stars): Works great!
This thing works great.  Remember to read the directions because if you operate the drill in the wrong direction, it will come unscrewed and you could end up with pieces in the pipe (which would not be good).  My dryer was not working well and I was getting worried that I would have to replace it until I realized that the vent must be clogged.  I bought this and the extension and it works like a charm- I have a very long vent pipe and had not cleaned it in a while (I admit it- I forgot to clean it for a couple of years).  You should have seen the crap that came out of the vent using this!  I can now shine a light down my vent pipe and it's almost as clean as it was when it was new.  Great product.