Product review (5 stars): Great Product
This is a great product, that we will definitely be using again.  We have a vent that goes up through the wall to the roof.  My husband went up through the wall, then up on the roof down and it really cleaned it out.  Read, and follow the instructions EXACTLY the way they say, you'll have no problems.  You do need the larger portable drill for the power.  We also used a shop vac with a blower & blew up through the wall, but really was not necessary.  The product can be repackaged to use multiple times.  I immediately noticed a difference in drying, I was drying a med. size load for 1hr. and it still wasn't dry.  Now I can dry  a larger load in 30-40 min.  We highly recommend this product.