We have approx. 100 of these casters and will get more, they are unused take offs.  Vintage 1950'.  They were take offs from my B52 Bar Carts, they were stored in underground caves in Kansas that is why they are blemished looking.  Unused surplus plate castors, half of these are swivel and half are rigid.  Sold in sets of 4 (2 swivel and 2 rigid) for $68.00.  Shipping to most locations in U.S.