Product review (5 stars): Worked great!
It used to take 3 cycles to dry a load of our laundry and after I removed the gunk shown in the picture with this product, it only takes one cycle.

Make sure you know the problem is a stuffed air vent in your house before you buy the product by feeling the air being put out at your dryer outlet versus the air leaving your house venting system.  If there isn't much airflow outside of your house, but there is a lot coming out of the dryer then you know you have a blocked vent pipe and this product will fix it.