On an equilateral triangle with a 1/8 inch (.32 cm) green border, 3 7/16 inches (8.73 cm) in height overall, one point up, divided into three sections, the upper section yellow, the dexter section blue and the sinister section red, a gun bendwise in front of a tank track and wheels all black surmounted by a red lightning flash bend sinisterwise. In the apex the Arabic numeral "40" in black.
Yellow, blue, and red are the colors of the branches from which armored units were formed. The tank tread, gun, and lightning flash are symbolic of mobility, power, and speed. The Division's designation is in Arabic numerals.
The shoulder sleeve insignia was approved on 23 September 1954. (TIOH Dwg. No. A-1-354)