A gold color metal and enamel device 1 3/16 inches (3.02 cm) in height overall consisting of a gold saltire, the ends couped at right angles, bearing at the center a black disc charged with a gold five-pointed star, all within and surmounted by a green annulet inscribed at base "IN TRUST" all in gold letters. Areas between the saltire and the annulet are pierced.
The saltire was suggested by the State Flag of Alabama and symbolizes support and confidence. The annulet is symbolic of complete control. The gold star represents authority while the black disc refers to prudence and wisdom. Green and yellow (gold) are colors used for Military Police units.
The distinctive unit insignia was originally approved for the 156th Military Police Battalion on 6 June 1975. It was redesignated effective 1 September 1981, for the 231st Military Police Battalion.