On a yellow shield 2 7/8 inches (7.30 cm) in height and 2 inches (5.08 cm) in width a blue rounded block figure 3 1 5/16 inches (3.33 cm) in height, elements 1/4 inch (.64 cm) in width.
Yellow is the color of Cavalry and the numeral 3 is the units designation.
The shoulder sleeve insignia was approved on 17 February 1928. (TIOH Dwg. No. A-1-273)