2 1/2" Diameter
2021.047.024 Circular patch. White cogged wheel with blue background and blue hexagonal center. The 6th Service Command Headquarters was located in Chicago, Illinois and the Command was responsible for the states of Illinois, Michigan and Wisconsin. The shoulder sleeve insignia was originally approved on 17 Jul 1941. It was amended on 14 Oct 1941 to change the background from olive drab to dark blue.