This wall cap is better then those I found in local big box stores. It is well made and should last for years. Mine seems to seal just fine. I'm using it with a Panasonic 240 ccm in line fan so there is no issue with the fan being able to open this cap. I would buy again

This is exactly what I needed for the 6 inch hose to the exterior from my hood fan. Heavy duty metal, well built, spring loaded door to prevent wind entry, A good product for my needs.