Also known as a unit crest or DUI, the Distinctive Unit Insignia is worn by all Soldiers (except General Officers) in units that have been authorized to be issued the device. It is worn centered on the shoulder loops of the Army Green Service Uniform (AGSU) and the blue Army Service Uniform (ASU, Enlisted only) with the base of the insignia toward the outside shoulder seam. DUIs are not worn on the Dress variations of either uniform, however.
Approved on 13 August 1968, the design of the 4th Psychological Operations Group Distinctive Unit Insignia is based around a quatrefoil that symbolizes the number four, which in turn is said to symbolize the “measuring intelligence” in esoteric philosophies; it also is the unit’s numerical designation and the number of major subordinate units in the Group.
The quatrefoil is divided into gray, white, and black areas, which reflect the three types of propaganda—half-truths, truths, and untruths, respectively—employed by PSYOP units. Lightning flashes represent the three primary delivery techniques used to disseminate propaganda, i.e., audio, visual, and interpersonal. A scroll at the bottom of the insignia is in the colors of the flag of the Republic of Vietnam, where the Group took part in eleven campaigns and earned Meritorious Unit Commendation and a Republic of Vietnam Civil Action Honor Medal, First Class. The Latin phrase “VERBUM VINCET” translate as “The Word Will Conquer.”
Full guidance on wear of the DUI is found in DA Pamphlet 670-1,
Section 21-22, "Distinctive unit insignia" and 21–3(d) and (e),
"Beret" and
"Garrison Cap," respectively.