I should probably note that I did not use this as a tube brush, but for my purposes it was exactly what I needed. As someone with old cast iron radiators, I have been searching for anything to help me clean out the last 60 years of dust that have accumulated in between the sections. This did the trick: it was firm enough to pull out the .5" of old dust and pet hair that had just been sitting there, but soft enough that it didn't scratch up the paint while doing so. I did supplement this with another, narrower brush as well (going across the radiator sections, while this one went forward between them). But if you don't have decades of stuff built up in there, this would probably be good enough on its own.
Rating: [5 of 5 Stars!]