Product review (4 stars): Proflex dryer vent duct
This is basically made of a continuous spiral wire covered with thin foil material. It is quite flexible and easy to stretch apart. It also bends around corners well. It is much better the semi-rigid type, which unravels easily and doesn't bend well at all. The only thing I do not like are the wired clamps. They are difficult to squeeze large and round enough to fit over the duct. When it is on, the clamp is not strong enough to hold the duct in place tightly. I had to use the worm screw clamps from my broken duct to secure it. The screw clamps are much better for this purpose.