Collection of six-inch and four-inch inspection ports. Not sold as individual ports. This former catamaran sailor couldn't own enough inspection ports!
The Universal port cover compresses and seals an entire existing six-inch port mount with a fat O-ring, should your port be damaged, split, or missing.
As indicated, two are new, in their original packaging. Most are "new-old-stock"—unused—two show tiny pry-scratches, but all would function perfectly. The 6" port at the lower right has no gasket, but can drop readily into other 6" ports. I'd cut out the center, bolt a small drying fan (muffin fan) to it, and save your original for summer.
Unless you pick it up in central NH, shipping will be extra, so advise of your ZIP code for pricing. PayPal works for me.