The picture below shows a larger view of this Old District 727 Aviation Division Advertising Celluloid Union Pin Back Button. This pin back button is not dated and the year that it was made is unknown. It is imprinted in red and blue on a white background. It pictures an airplane propeller a framing square and a caliper. The tin back has an embossed union mark and there are two union marks printed on the edge. It is marked on the front and edge as follows:
DISTRICT 727 AVIATION DIVISION IAM A.F. OF L. MF'D HEINRICH SPECIALTY COMPANY LOS ANGELES
The pinback buttonmeasures 1-1/4'' wide. It appears to be in near mint to mint condition as pictured.