Product review (5 stars): Saved the day!!
We have a tri-level house with the dryer on the bottom of the house.  The length in one package was the perfect length.  My suggestion is to be sure NOT to use a power drill...its not worth it.  These rods, although very bendable, will twist off in the duct if caught while using the drill.  Then youll have a bigger problem.  Just user your hands and twist it CLOCKWISE whole shoving in/out.  This method will work out clogs while keeping all the screwed rods tight.