Product review (5 stars): This works just as is described
I must admit I was skeptical that this would perform as well as the description on "Product Features" displayed here at Amazon.com.  Our dryer duct is over 30 feet long and I had taken it apart to clean on several occasions before. Getting all the lint out of even more than one 3 foot section at a time was a challenge as the lint seems to stick as though someone glued it in place. I ordered the Gardus R3203612 LintEater 12-Foot Extension Kit to go with the cleaning kit.  The extensions are the same as the rods that come with the kit and extend the reach an additional 12 feet.
I placed the vacuum attachment on the end where the dryer would be connected and went outside to feed the  brush with the rod into the duct (per instructions) one rod at a time.  It seems to be a simple operation, with the adding each rod separately until the end is reached.  I my case, I had to finish by going into the house to clean the last 6-8 feet from inside as the 24 length was still not long enough to reach the end.  The vacuum attachment has a port for the rods in that scenario, also.
Upon looking down the duct with a flashlight, it looked surprisingly clean.  I would recommend this item, especially if the lint build up in your dryer vent is difficult to clean out.