A sword 1 3/8 inches in length laid horizontally across the upper part of an open book. Below the sword and across the lower corners of the book two laurel branches crossed at the stems. Insignia 13/16 inch in height of gold color metal.

Prior to World War II, all officers were assigned to one of the arms or services and had an appropriate branch of service insignia. In November 1941, an insignia was created which consisted of the Coat of Arms of the United States within a ring, for officers who were not members of, or on duty with an arm or service, and the Specialist Reserve. Following World War II, unassigned officers became a part of the Staff and Administrative Reserve Section in the Army National Guard and Organized Reserve Corps.

The Insignia was designed by Miss Will of the Heraldic Section, Office of The Quartermaster General and approved 5 February 1948. On 23 September 1949, the Staff and Administrative Reserve branch insignia was redesignated for the Staff Specialist Reserve branch insignia. The Staff Specialist is still a branch of the US Army Reserve (formerly the Organized Reserve Corps) but has no equivalent in the Regular Army. The book represents regulations, while the laurel sprays symbolize the honors received in the administration of military regulations. The sword represents the military nature of the regulations.