I have no idea what it is, except it not being a coin, but if I read the characters correctly as this (and read them right to left, as in Hebrew), it appears to translate directly as “shut up” or “be quiet”. Hebrew isn't my strong point though (LOL).
More liberally, it also roughly translates as “got it?” or “are we all clear on that?” in the sense of there being no opportunity for disagreement.
One online Jewish lexicon notes the following under the section “Who Uses This (phrase]?”…
Jews: Jews of diverse religious backgrounds and organizational involvements
Camp: Jews who attend or work at a Jewish overnight summer camp
Israel: Diaspora Jews who feel connected to Israel and have spent time there
Organizations: People involved in a professional or volunteer capacity with Jewish nonprofit organizations.
If the translation is correct, my money would be on some kind of acknowledgement or achievement relating to the second or last of those four.