Product review (5 stars): Works like a charm
A solid investment.  I have a dryer that vents up through my attic and out my roof.  I've always kept the lower part of the vent that attaches to the dryer, cleaned regularly but it's a bit of a trick to clean the vent pipe all the way out to the attic.  We ran this cleaner from the laundry room up, and then from the roof vent down.  Works like a charm.  My 17-year-old dryer works like new again.  It was taking an hour or more to dry a load of laundry, now it takes 40 minutes.  I bought this several months ago and used it right away, and I've seen my natural gas bill go down because of less drying time.

The safety factor of clearing lint that becomes a fire hazard is well worth the investment in this item.