There is some confusion regarding which unit this beret flash and background trimming are designated for, with all online uniform and insignia vendors except us identifying the unit as Company H, 122nd Infantry Regiment. But according to insignia expert Barry Jason Stein in his reference book U.S. Army Patches, Flashes and Ovals, both the flash and oval were designated for that unit before being redesignated for Company H, 121st Infantry Regiment in July 1992, a claim that matches up with the date that the two Infantry Regiments were consolidated into the 121st Infantry consisting of the 1st and 2nd Battalions plus Company H.
Beret flashes, also called organizational flashes, are worn by all personnel in the unit. The 121st Infantry Regiment, Company H flash is worn on the maroon beret to signify the unit’s Airborne status, centered on the beret stiffener so the flash be aligned above the wearer’s left eye.
Officers wear their non-subdued insignia of grade centered on the flash; Junior Enlisted Soldiers and NCOs wear their Distinctive Unit Insignia (or Regimental Distinctive Insignia if their unit lacks a DUI) in the same fashion. Exceptions to the DUI/RDI rule for Enlisted personnel include the Senior Enlisted Adviser to the Chairman of the Joint Chiefs of Staff (SEAC) and the Sergeant Major of the Army (SMA) and SMA office staff. In both cases, collar insignia designed for these specific offices is worn on the beret flash in lieu of rank insignia.
Technically called background trimming, the oval is worn beneath Air Assault and Parachutist badges, with the main portion of the badge centered on the oval. The two items are considered as one for measurement and placement purposes on Service Uniform coats (AGSU and ASU), Service Uniform shirts, and the blue or green Army Maternity Tunic (female Soldiers only).