I'm calling it a rivet as it holds the base of the insides together. When you look at the back of the cluster gauge when everything is together there's a hole between the two posts where this "rivet' sits in the middle. It should not touch any part of the housing, if it does and you reconnect the battery bad things happen. On mine that rivet is a little loose, so when I carefully tighten down the first nut on the posts I made sure it didn't move to mess up the ohm readings listed above.
