This looks to be a very specific Air Force patch from SAC headquarters in Omaha Nebraska. Used during the Vietnam War era. Dean C. Spraggins, USAF (retired) wrote: "The Strategic Reconnaissance Center was a HQ agency (SAC/DOR). Tasked with command and control of recce assets, it had it very own specialized command post, under H wing of Bldg 500." It measures 4 1/4" by 4 1/2" and is in very good used condition.