Product review (5 stars): LintEater is right!
I used this kit at my rental property when my tenant was complaining about the dryer not drying clothes properly and taking forever.  I spoke to an appliance repair man and he said if the temperatures are right inside the dryer that it would mean clogged vents.  He was spot on with the problem.  I bought this kit , looked at directions real quick and went to town on the dryer vents. I was shocked how much lint this thing cleaned out of the vents.  It fixed my dryer issue and my tenant was happy.