I was Plumber back in the 80's - it was my parents family business .
they bought Ken Prentice Plumbing & Heating in Damariscotta , Maine in 1976 . It went on to become Mid Coast Energy Systems . I am going to bring his birthday present to him tomorrow - He is 82 - I will bring the tool .
some kind of pin wrench for a specific use, it looks to me like a proprietary tool that came with a kit, and was only meant for that one thing. I've seen other types of pin wrenches that were single use specific, but never the one you have as far as I know.