Product review (4 stars): Really liked - wished it had a shorter brush also.
I really didn't think my dryer venting was that dirty with lint (20 yrs in house) but I ran it through from the outside of the house and a huge clump came from somewhere in there.  I had pushed it through with all the extension rods until it hit the turn in the vent.  I did it manually.  Then I went inside, took the vent pipe off the wall and ran it through there.  I also did it to a bath ceiling exhaust fan I could reach from the outside.  I only wished they made a 2.5 inch long x 2 to 2.5 inch wide brush (6 inches is too long) so I could run it through the interior side of the ceiling bath exhaust fan so I wouldn't have to take the whole fan out.  That's the reason for only 4 stars. Toilet paper makes ALOT of lint if you've never looked at your bath exhaust fans before.  I used the wider brush for the range hood exhaust vent outside (got a wasp's nest out of there!) and now have to figure out how to remove the microwave front so I can attack the venting from the interior side.