It is a small metal button with a bend over tab.you bend the tab over a pocket, lapel or something else so the button shows and stays where you put it.
The button was a give away from a comic book store after Superman got beat to death and 4 people showed up claiming to be the new Superman. Each had some of Superman's powers. One was the Kid, another was the Kryptonian, one was the Man of Steel, and there was one other I can't remember.