B58-733 BULLS-EYE PLUMB BOB. Stanley No. 47-173. Uncommon flat plumb bob design, with a rotating steel wire so that you can either hang it vertically like a traditional bob or horizontally and sight through the center. Patented in 1974; these were more popular in England and were manufactured only for a year in the US, but this one is marked "Made in the USA." Made of some nonmagnetic metal, maybe aluminum, with fully intact red enamel. Fine 80-150