Product review (5 stars): Gross but very satisfying results!
I had years of buildup in a 27 foot duct that ran under the house with a right angle in the first 2 feet. After living here 3 years, my drier started giving me an error message about air flow. I invested in 2 of these kits to connect together and try to clean it out.
After reading other reviews, I was very nervous about It coming apart inside the duct. I tested the attachment and un-attachment of the drill before putting anything in further than I could reach and was glad I did because the first time I unattached the drill (I wasn't holding it right) the rods came unscrewed (duct tape reinforcement and all) which would have been disastrous in the duct.
After that, I attached one rod at a time and pulled it back up to clean the lint off. Each time it went down with one more rod and came back up with more lint. By the time I got past the halfway point it was a lot easier and less lint came back.
All in all, I pulled up about 5 lbs of lint (filling an entire plastic grocery bag. Ewww). I didn't make it quite to the end but could see the brush from the outside end and it was clean.
I feel so much better about not burning down the house now and my next load of laundry dried in half the time.
This was a small investment for a lasting peace of mind and much quicker laundry times!!