What do I have here ?
Cleaning up a shelf, I found this tool and don't remember it at all.
It is 3 1/2" long and has a plunger that either has a spring or a leather washer inside and seems to push or pull air when activated. One of the curved parts is firmly attached and the other is not. The loose one doesn't want to thread onto the threads on the body , though it seems to be threaded and does slide onto the fixed one.
On the plunger end is PERFECT , and a star.