Insignia Description
A Silver color metal and enamel device 1 1/8 inches (2.86 cm) in width overall consisting of a shield blazoned as follows: Azure (Teal Blue) a saltire Argent charged with two pyrotechnic projectors of the first, overall a mullet of four points Tenné fimbriated of the second. Attached below the shield a Silver arched scroll inscribed “AD ARCANA TUTANDA” (To Keep Official Secrets Safe) in Teal Blue letters.

Symbolism
Teal blue and white are the colors associated with the former Army Security Agency Battalion. The pyrotechnic projectors allude to the signal and reconnaissance missions of the unit. The four pointed star refers to the four battle honors awarded for service in World War II and also symbolizes intelligence, reconnaissance, communications and signal, vital functions of the battalion. The color orange further alludes to its signal function. The saltire is symbolic of the southern states that make up the Third Army area, the home of the battalion.

History
The distinctive unit insignia was originally approved for the 305th Army Security Agency Battalion on 27 September 1957. It was redesignated for the 305th Military Intelligence Battalion on 18 June 1990.

Source: The US Army Institute of Heraldry