This was the only vent cap that I could find with 6" round ducting, for use with my Air Exchanger input. Although it worked, with some difficulty and modification, I wish it were made of plastic instead of heavy duty aluminum. But, like I said, it was the only one that I could find, so I'm glad I found it.

Excellent fit for 6 inch outlet. Spring keeps door closed during high cross winds, and stops inadvertent flapping.

I love the looks but it was too small I did ask about the size I did want 5” I was told that they only have 6” I reply that size will not fit too big but they think it’s ok. I was right I have to have a company cut hole bigger and put insulation inside. It is a nightmare it cost me a lot of dollars. I

Keeps birds out but slightly noisy in high winds. Otherwise much better than our previous range hood.