Clear, well-printed back variation for Block & Kuhl Co. active wear stores from the M101-4/5 sets printed by Felix Mendelssohn. The photo shows Hall of Famer Ed Walsh circa 1910, when Chicago wore its distinctive "SOX" striped jersey. Its PSA VG 3 grade reflects slightly rounded corners and a diagonal crease at lower right. This set proves exceedingly tough and PSA has graded just 21 Block & Kuhl cards total. The population report shows this as the only graded Ed Walsh!

M101-4 and M101-5 are sets Mendelssohn created with 200 ballplayers of the mid-1910s. Card backs often featuring ads from a range of stores and companies, no doubt for their own marketing purposes. Contemporary advertising shows some stores giving groups of cards away as an incentive for in-person shopping and others sold their sets by mail order.