Distributor wrench

You can still buy them. Even HF has them. I have 2 of them. One is double ended 1/2 X 9/16. The other the handle can be rotated to help get at the bolt better. It has a 3/8 extension socket end on it, to rotate the closed box end on it.
Used them on aircrfaft in the Navy, for certain things. They come in handy for different things, at times.

Dave