Product review (2 stars): its thin metal that bent easily when trying to adjust to the right size
Its inherently difficult to install, since its designed to fit into a small space, its thin metal that bent easily when trying to adjust to the right size, and you have to cut it before you can fit it, and by then you can't really return it.  Basically telescoping it back and forth an inch or so to get the to exact size, after eyeballing it, and putting it together, would jam up easily, and I'd try to force it, when I finally got it in there were leaks, and being in a tight space getting the duct tape around the leaking areas was a pain.  Really wish It bought the regular 4" pipe kit and not tried to save 2 inches.