They are no longer manufactured. I looked everywhere for one for my 8600 and couldn't find one... I had to find an old 8000 and scavange the pinch roller from it.
I had emails out to every shop that deals with graphtecs.. even mentioned if they had a salvaged graphtec I'd take a used one from it just to add to my machine... Waited months and no luck.
Not the news you want to hear

but look for a used 8000 being sold for parts as that's pretty much your only option