Product review (5 stars): Highly recommended!
Very well made, high quality, durable product.  I used it to clean the dryer vent with a 4 feet vertical run followed by 15 feet horizontal.  It had 10 years of accumulated lint and came out perfectly clean.  The flexible rod assembly was too short to do it all from one end (12').  I went as far as I could from one end of the vent and then simply continued from the other end of the vent.

The included shopvac adapter is slightly different than the one shown.  The hole for the 2" hose is off-centered with a smaller hole to insert the flexible rod.  This allows the shopvac and the drill to be operated from the same end which is how I operated mine.

The brush still looked new after this, which clearly shows that this is not a throw-away product but rather one that should last a while.

Finally, the instructions are very detailed and clear, a rare thing nowadays.