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.
More 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.
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The 556th Personnel Services Battalion Distinctive Unit Insignia features a feather pen with a nib that resembles the tip of a wrench to denote service at all levels; the scarlet lighting flash on the feather is taken from the Shoulder Sleeve Insignia of the 25th Infantry Division, the Battalion’s parent organization, and recalls the organization’s renowned speed of maneuver that led to its nickname, “Tropic Lightning.” “Service Always First” was the motto of the unit, which has been inactivated an uncertain amount of time since its last tour of duty in Southwest Asia.
The 556th Personnel Services Battalion was originally constituted in the Army of the United States the 556th Replacement Company and activated in North Africa on 25 August 1944. It took part in the Rome-Arno campaign before being disbanded in Italy on 8 August 1945. Following the end of the war, the unit was reconstituted as the 556th Replacement Company in the Regular Army on 27 September 1951 and activated on 7 November 1951 in Japan. For its support role during the Korean War, the Company was awarded a Meritorious Unit Commendation for service in the Pacific Area between 1951 and 1953, but it was inactivated on 15 June 1953 in Japan.
In January 1968, the Company was redesignated as the 556th Personnel Service Company and activated at Schofield Barracks, Hawaii, but was subsequently inactivated nine months later on 1 October 1968. Nearly two decades passed before the Company was reactivated on 16 July 1968, and on 16 September 1995 the company was reorganized and given its final designation: the 556th Personnel Services Battalion.
Though assigned to the 25th Infantry Division, the Battalion was often attached to other units to provide much-needed support in the War on Terrorism, and as a result several detachments from the 556th Personnel Services Battalion were selected for Meritorious Unit Commendations. In June 2008, Detachment C was awarded an MUC for service between 9 July 2006 and 23 June 2007 while attached to the Special Troops Battalion, HHC, 45th Sustainment Brigade. Just a month later, in July 2008, the Battalion’s Detachment A was tapped for its service between July 2006 and October 2007 while attached to the HHC, Combat Aviation Brigade, 25th Infantry Division.
On only one occasion did the Battalion’s Headquarters and Headquarters win a military decoration in the War on Terrorism: for its service in support of Operation Iraqi Freedom between 25 September 2006 and 24 September 2007, the HHC was selected for the Battalion’s third MUC, with the announcement specifically citing how the “unit significantly improved combat operations by flawlessly executing the joint theater reception, staging, onward-movement and integration missions."