Product review (4 stars): the outer foil layer held up pretty well to me fidgeting with it to get it ...
Exactly what I needed.  Not 8 ft but I was able to cut it to size and save the rest for future use.  I didn't use the included clamps and bought the whirlpool ones for an extra $2.

Not sure yet how it will hold up to high heat since I haven't used the dryer all that much.  but, the outer foil layer held up pretty well to me fidgeting with it to get it onto the hard vent side.