It's just for those horrid pc ports they made in the 90's. Sort of interesting, but nothing to really get excited over. They pop up now and again,it's usually not profitable enough to even try to sell.
There are a few of them: for ISA slots, PCI slots, PC98. Multiple revisions also. It allows you to hook up saturn control pads. there is also a card for the virtua gun, but you need some specific graphic card.
My uncle used to have the VF2 port. Still got the Saturn controller. I was too young to remember if it was any good or not.
I also have that circuit board with FDD some where in my drawer. No idea how long it's been there along with other forgotten stuff...
