Product review (5 stars): If your dryer vent is clogged, this is your answer!
The actual brush and rods that come with the product, work wonderfully.  I also bought 8 more rods as our exhaust run was too long.  We got sooooooo much lint out of my son's venting (probably  garbage cans worth).  It took about 3 hours (due to the length of the run, as the lint brush worked like a charm, just so much lint. We had to keep pulling the brush out dragging with it all the lint). It took two of us because we did not add one rod at a time.  We fed several rods into the venting together.  It was actually fun to see how much lint was removed.  After the job was completed, the dryer dried a load of clothes in 47 minutes where before cleaning the vent, a load was still very damp after 2 hrs of drying (that was the push point to do something about the problem, besides a significant drip at a joint of the venting).  We also used an electric blower to blow out residual lint to the outside and jerry rigged the blower up to the black adapter with the small hole to insert the rod.  That sped up the job.  We used the blower and the brush at the same time.