Product review (5 stars): It Really Worked ! ! !
I was in ACE and saw this.  I have a 20 foot long - under the garage slab - dryer duct.  I had cleaned it before using a real long piece of rebar with a brush taped on the end from the outside and cramming a vacuum hose down from the inside.  I busted my butt!  So I bought this thing - thinking it'll probably break in the first 2 minutes but anything that might work without the fight I usually went through was worth a try.  Well - It worked like a freakin' charm!  I cleaned the whole duct from the inside.  Taped on the vacuum adapter with the side hole for running the flex rod through - stuck in the shop vac hose, connected to my variable speed drill and voila!  Every thee foot you have to stop and screw on another flex rod - but no big deal.  This thing cleaned it out like it was brand new and I didn't break out a sweat!  I bought this a couple of months ago but put off cleaning because I was sure it would break and I'd be back outside with my rebar.  I just finished and had to take time to recommend something that actually works - you can't leave a post on the mfg. site so I wrote it here!

Get one!