Ever since the 1870's baseball card collecting was an enjoyable pastime and in 1939 the centennial year never more popular. The most prominent card producers were Gum Inc. of Philadelphia "Play Ball America" a 161 card set and Goudey Gum Co. of Boston Mass. & its affiliate World Wide Gum of Montreal Canada. Goudey offered a large format picture of baseball's current stars in a sepia tone and black and white form cataloged as R303a and R303b. In 1937 Goudey purchased National Chicle Co. and the rights to their card offerings. In 1939 they produced the Goudey "Diamond Stars" as R303 A&B.
World Wide Gum offered a smaller portrait of Major League and Minor League baseball stars created as "Diamond Stars" they were cataloged V351 and were printed in Canada.
Gum Inc. "Play Ball America"
"World Wide Gum" a Division of Goudey Gum.
World Wide Gum V351 was a 25 card set, Each card measured 4 x 5-3/4 printed in Canada. They were exchanged for wrappers at the candy counter.
Goudey Gum. "Diamond Stars"
Goudey R303A was a 48 card set, each card measured 4 x 5-3/16 in a sepia tone. The point of sale is not clear they were either exchanged for wrappers or sold at the candy counter.
Goudey R303B was a 24 card set, each card measured 4-3/4 x 7-1/4 in a sepia tone or black and white. They were purched at the candy counter with gum.