506 prefix means made by Columbian. It appears to be a fixed-base vise (no swivel base), which I prefer. They are very solid. Assuming jaws are in good shape, andno cracks or other issues that cannot be fixed with WD40 and steel wool/scotchbrite pad, that vise is easily worth $75, IF YOU NEED A VISE THAT BIG. For daily use, usually a 5" vise is more than adequate.