Challenge Coin
Other names for a challenge coin are Military coin, unit coin, commander’s coin, commemorative coin, and memorial coin. The coins serve to identify the holder as a member of a particular group, or unit, and are tangible symbols of their pride and respect for the organization.
As tradition holds, members are “challenged” to produce their coin, and if successful a free drink is coming their way courtesy of the challenger. If the member does not produce their coin, a drink is coming to the challenger courtesy of the person challenged.