Product review (5 stars): Works as expected.
I used this on my dryer duct and it worked great. The plastic rods are fairly flexible. I have a 90 elbow after about 6 feet of straight duct and I was not able to get past this, but I expected that. I'm guessing if you had an elbow closer to where you are inserting this you may be able to get past it. I did not try using this with a drill and just did it by hand.