The clunky "W" catchall used by Jefferson Burdick in the American Card Catalog was meant to signify "album cards" and covered items issued anonymously without dating. This circa 1910 set is well known in the hobby and represents a fairly early entry in the Strip Card sweepstakes. The SGC Authentic grade reflects the nature of these cards, meant for separating with scissors, usually by a child.  This issue is a scarce one, with a mere nine cards in the SGC pop report and none higher than a 3 (the entire set has nothing graded above a 3, in fact) and the lone PSA is graded as a 1. In other words this is tough, scarce card of a Hall-of-Famer. It may be a long time before another one of these pops up.