The picture shows a view of this Old Enameled Automotive Service Men's Association Stud LapelButton. This button appears to be made of brass or copper. It is enameled in blue and white. It has a screw back section. The year it was made is unknown. It is marked on the front and back as follows:
Automotive Service Men's Ass'n Massachusetts Service Men's Association Incorporated Boston Badge Co. Boston, Mass.
It measures 5/8" wide and it appears to be in mint condition.