Product review (5 stars): This Brush saved me big money on fixing dryer
Before using this tool it took 1-2 hours to dry a standard load of clothes
I used the brush from the wall duct behind the dryer upward and from the roof vent down.
The brush found a large blockage of int and broke it up.
 In the online video the recommendation to tape the joints was a big big help.
Now the dyer uses a normal cycle time to dry heavy cloths.