Product review (4 stars): Very low cost hood, watch your size
Order arrived promptly and was packaged correctly.  I ordered this product because it had the flapper included.  Silly me. I hadn't take down the old unit first.  This one has a rectangular vent connection, and my house has a round vent.  This units cousin comes with a round vent, but I bypassed it because the flapper had to be purchased separately.  The individual flapper purchased separately had rather poor reviews.

This was now beyond my installation capabilities.  Brought in my handyman.  He had tin snips, etc. and went to the box store to buy all the connectors we needed to make a rectangular tube fit a round hole.  All of the pieces were still less than the $14 I'd have to pay Amazon to ship this one back.  It turns out, the round to rectangular conversion wasn't the problem.  This unit is built square, and the opening where I was trying to put this hood wasn't. It took 4 hands to hold the unit while we banged and shoved to get this unit into place. My house was built in 1985, so I wasn't expecting this much trouble to get this in place.

Once in place, it worked like a charm.  It wants a 60 watt incandescent bulb which aren't sold any longer.  There were no instructions if a florescent bulb could be used instead.  That needs research.

Two days after installation, we had 35+ mph winds.  The flapper didn't make a sound.  The old flapper banged around horribly.

In summary, before you buy, know if your round or rectangular, and keep a extra pair of hands around when installing. Bending backward over a stove with your hands above your head is hardly a single person job.