Notice he give a long description of it lol, doesnt say if its single phase or 3 phase (99.9% cert its a 3 phase) hate that when people cant be arsed to describe an item with some detail.
He doesn't even say it's a miller but it is, as it's very similar to mine. If so, I expect it is single phase 208v, 300v or 400v. You just change a jumper inside to suit. I'll be interested to see what it fetches. The starting price is already double what I paid for mine!