Product review (2 stars): bad design for 10-foot ceiling height
Stupid design. Looks great, just like the one that came with the hood only longer. Dumb part is that the one that comes with the hood only goes up to a certain height and this extension only goes as low as a certain height and it leaves about 2 or 3 inches between the two where neither one will work. So if you have a 10-foot ceiling there is a good chance that you can't use either one.  I had to cut down this one in order to make it work, but you have to cut the longer piece, not the shorter one, and the longer one is on the outside so your cut is visible and really should be done by a local machine shop to keep it from being ugly.  I didn't, I just used tin snips, but even being very careful it still leaves an edge that looks all dimpled with tiny little bends (even though I have done a lot of sheet metal cutting of duct work in the past).  If they had the long piece sliding up inside the short piece instead of the other way around, it would hide the cut edge and not be a problem.  I know they do it the other way around so that when you are looking up at the seam you aren't looking into the gap between the pieces, so they really needed to just make this long piece a few inches shorter so either the standard one or this one would cover all ceiling heights.