Product review (5 stars): Works as promised
It works as promised, make sure you read the instructions carefully and FOLLOW THEM! I would stress on one point someone already made: Only hookup on piece of stick and push it in to the vent before adding another extension piece. This is very important. I tried to take short cut despite the warning on the second round of cleaning and ended up bending one piece plus hurting myself!

I have a vertical exhaust vent: I connected shop vac near dryer side. And pushed the cleaning brush from the exhaust side. Got half pillow case full of lint from 12' vent that was not cleaned for 7 years. We were very diligent about cleaning dryer filter every cycle so my vent did not had any drying sheets or cloths in it!