A 2 inch (5.08 cm) square one point up, divided horizontally by a zig-zag line with two points down, the lower part black and the upper part red, the latter charged with a yellow conventionalized sun issuing from behind the partition line; all within an olive drab border.
The device, the square, is a geometric arrangement of mountains found throughout the Western Defense Command and which also forms the letter "W." thus being truly symbolic of the Western Defense Command and indicating protection.
The shoulder sleeve insignia was approved on 18 December 1942.