I have a few pair of those, and some of the silver ones too.
Sucks how the whole NWTM thing got messed up in the end.
Looks like Christmas tree balls.
At a company where I worked the operations manager had the company’s pair of balls. When major important decisions were about to be made, he brought them out of the cabinet.
The steel balls were about 3” in diameter and were welded to a short piece of 3/8” Proof Coil Chain. It was not light. smile.