Product review (5 stars): Worked Perfectly!
I'm a stickler about cleaning the dryer's lint filter, but I have never cleaned the vent -- ever.  I thought the lint would fill my laundry room, but it just filled the vacuum canister. This brush knocked what lint there was loose so I could vacuum it right up from the vent opening. It will now be an easy once a year maintence chore thanks to this clever brush and it has already paid for itself!