A Silver color metal and enamel device 1 1/8 inches (2.86 cm) in height overall consisting of a shield blazoned: Azure a saltire voided Argent, overall a prickly pear cactus Proper entwined with a snake Or, a chief ermine. Attached below and to the sides of the shield a Blue scroll inscribed "ESTO PERPETUA" in Silver letters.
Blue is the color for Infantry and commemorates the initial organization in 1846 as the 2nd Kentucky Volunteer Infantry Regiment. The Civil War service represented by the white saltire cross voided blue from the flag of the Confederacy. The Mexican War service (Buena Vista) is represented by the cactus and snake from the Mexican flag and the World War I service by the ermine chief from the arms of both Brittany and Nantes. The motto translates to "May It Live Forever."
The distinctive unit insignia was originally approved for the 149th Infantry Regiment on 10 December 1925. It was amended to correct the description on 3 August 1926. It was redesignated for the 241st Tank Battalion on 9 January 1956. The insignia was redesignated for the 123d Armor Regiment on 23 September 1960. It was amended to change the symbolism on 2 October 1969.