Product review (5 stars): Works well, but make sure you have enough sections!
These do just what they are supposed to.  The way the vent pipe is put together, it is a one way trip pushing this through - the lip of the vent pipe catches the brush if you try to pull back on it.  I've got a wicked long vent run, and can see the brush with a pile of lint in front of it about 6' from the end.  Will finish the job once I get my 3rd kit on Mon.