Product review (5 stars): Works Great
I checked out the hardware stores Home Depot and Lowes and they didn't really have what I needed.  I needed a roof vent for 6" duct.  This product is perfect for that.

This item arrived a while back and I installed it today.

I read multiple reviews about this and other roof vents.

There was one that said this vent was actually brown.  It looks black to me.

There were some reviews that said the vent arrived damaged.  Mine arrived in perfect condition.  It was in a box that was placed inside another box.  The vents are easily damaged as I bent a corner carrying the vent to the roof.

I think that the  collar to attach the 6" duct could (should) be longer.  The directions tell you to cut a 7" diameter hole.  I did that and didn't have any problems connecting by 6" flexible duct work with a 6.5" Hose Clamp.  I would rather have cut a 6" hole but I think if I had done that I would have had trouble connecting the 6" duct work because of the short length of the  collar.

The bird guard kept falling out of the vent once I was on the roof which was rather annoying but I don't think it's going to fall out now that the roof vent is mounted.

The damper works fine and is very quiet.