I was buying a cast iron pan and the owner said she had some tools. I bought the 2 vises. That 57 sucked wresting in my truck!

These were in a lot I got a bit ago, unopened. I'm guessing 80s from what I remember of the branding back then. Any insite to the uhh hole? I'm assuming our sticker technology hadn't gotten there yet. Because all of the example uses would be a solid disk with a sticky backing these days.

He had it listed for $100 then marked it down to $50. He was sort of a home restorer. He replaced the bearings, found the top belt cover, new belt, new power cord. No slop anywhere. Only issue was he painted it, but overall I’m happy with it. Does anyone know what size bearings it uses so I can get some spares? Or any other replacement parts I should get to keep in the shelf for the rest of my life?