2-13/16" wide oval button with metal back and bar pin with collet suspending 4.25" ribbon. Pictured is the "Cummins Diesel Special" with text above and below "Cummins Engine Company, Inc./Columbus, Indiana." Ribbon below specifies "Memorial Day/500 Mile Race/1952." Pictured within the car is race driver Fred Agabasian. This was a revolutionary car by Cummins which featured turbo charging. It was also the first Indy car tested in a wind tunnel for aerodynamics. It became the only diesel to capture the pole position. The car retired mid-way through the race as the turbo charger inlet became clogged with rubber debris from the track but it established turbo charging as a viable technology. Button and ribbon are in superb NM condition displaying Mint. Rare. Paul Muchinsky Collection.