This 25-pin set is also known as the "PR4 Baseball Drawing Set" as the player portraits are actually line drawings. The pins measure approximately 13/16" in diameter. The pins are printed in gray and blue on a yellow background. The set was probably issued some time in the early thirties based on the selection of players in the set. Be careful not to get these pins wet as the inks are water soluble.
Disclosure about relationship with EPN. When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.