Product review (4 stars): As advertised...if you only need 12" with no difficult bends
Worked as advertised and per the instructions, as long you don't have multiple hard right angel bends and your total length isn't more than 12 feet. I wouldn't recommend trying it without a variable speed drill...can't imagine how it would work if you had to turn in by hand.  Unfortunately, my pipe length was longer than 12', so I wasn't able to get 100% of the pipe.  This may not have been a problem, but it wasn't flexible enough to navigate the hard 90-degree bend in my wall, so I wasn't able to clean the entire length.  It would be nice if you could buy additional 3' sections for longer pipe runs.