Members of the United States Navy Reserve who go on inactive duty are issued a button or pin by their separating command indicating that their status in the Reserve. Inactive duty Reservists take part in weekend training once a month and conduct annual drills, but this time does not count an accumulation of active-duty service. They are not issued to members of the Navy’s Reserve Officer Training Corps, and they may be worn with civilian clothing only.
You may learn more about the requirements for this pin by reading MILPERSMAN 1910-810, Issuance of Certificates, Buttons, and Pins Upon Separation on the Navy Personnel Command Web site.