Product review (5 stars): Works great!
Great cleaning device. I should have bought the extension kit (sold separately), but since I didn't I had to improvise. Definitely don't push it partially in and quit if it's not long enough, that's what I did and it created a total blockage. I ended up using it from the dryer side, then going from the outside in. I turned the dryer on the cool setting and ran it while cleaning from the outside so that when stuff got loose it'd blast it out. If you do this, don't look in the hole or you might catch junk in the face!

I couldn't believe all of the junk that came out of the dryer vent. I think there was like a failed attempt at a bird nest the blew out in addition to probably a pound of dryer lint. It sounded like a bowling ball coming through right before it all dislodged, sure am glad I ducked before it blew out!