This variety earned its nickname from the unusual configuration of the reverse die breaks, which look similar to the seams on a baseball. Researcher Bill Bugert designated this as variety WB-2 under his new numbering scheme, though it sometimes appears as WB-102, Die Pair 2 in auction catalogs (WB-102 encompasses more than one die combination). Interestingly, the WB-2 variety was struck on two different occasions, with the WB-3 variety sandwiched in between.
Bugert called this variety Rarity 5 (31 to 75 examples known) and noted that "Almost all found grade XF or below." The MS62 example illustrated above is the finest known to us and it came through the PCGS grading room in November 2017.