Product review (5 stars): Worked much better than expected
It is amazing how well this worked. I have a 30 foot vent run and I didn't want to clean from both sides, so I used two sets of extensions. I had no trouble pushing the brush through the entire length with two 90 degree turns. One tip: I used a shop vac as a blower starting from the dryer side and pushed towards the outside. For such a long run, I noticed that the blower actually helped push the brush along and keep it straight. When I tried pushing without the shop vac running the brush started jamming in the pipe. This is an outstanding product and I can recommend it without reservation.