The product is an opportunity to choose your own 1991 Upper Deck baseball card with an error featuring the baseball hologram on the back of the card from the 1990 Upper Deck set, sometimes referred to as the rare 'b' set variations. These standard-sized trading cards are made of 20 Pt. card stock and feature players from the Major League Baseball (MLB) season of 1991. Manufactured by Upper Deck, these original cards are a collectible item for fans and collectors of sports trading cards.