Orel Hershiser (card # NNO31)
Here's what The 2009 Standard Catalog of Baseball Cards says about this set:
Eyeballing the printed checklist there were from 3 to 7 players per MLB team.1993 DiamondMarksWhile they look like baseball cards and were sold in foil packs like baseball cards, DiamondMarks were licensed as book marks. Issued by Barry Colla Productions, the 2-1/2" x 5" cards feature Barry Colla’s trademark high-quality player photos on front and back. The UV-coated fronts feature black borders with the player’s name in white above the photo and a color team logo beneath. Backs, also bordered in black, feature two color player photos in an open book design. There is a portrait photo on the left and a head-and-shoulders reproduction of the front photo at right. A bookmark with team logo is incorporated in the design. The 120-card set is unnumbered and is arranged in the checklist below alphabetically within league and team.