This is a 100% Genuine Tiffany & Co fountain pen, purchased at original store on 5th Ave store in New York City! Silver clip and ring need a little polishing, but otherwise in great shape. If you take it to a Tiffany store, they can clean it up for you. My phone won't take close-up enough pic to read the engraving on the nib, but it's beautiful craftsmanship.
It's set up for cartridge now, but can also take a converter available at Tiffany's.
Full disclosure: It was awkward opening to see the refill and may require a minor repair. It seems like some glue has given way in the part above the threading. I'm certain someone at Tiffany & Co could easily fix it, if you can't do it yourself.
An identical, brand-new version of this pen sells for $1600+
I haven't used it in years and have new favorite pens now, so this treasure is yours for the taking.
I'll take cash or venmo. I'm in Englewood, a few blocks from Hampden and Logan.