Thanks for the inputs. The shunt is isolated from the aluminum body as is the vertical stud and threaded knob. The large hole goes on the bat. post and the vertical post accepts the cable I think. Current can flow through the body and if the knob is tightened pass through the shunt to the cable. Must be some sort of accessory for troubleshooting with a meter. It would be great if I could use it to test current but would need some direction.
Dick