The 1991 Upper Deck "The National" Promo Set features trading cards of baseball legends Nolan Ryan and Reggie Jackson, as well as other notable players from the Major League. This set, manufactured by Upper Deck in 1991, includes four standard-sized cards made of card stock. The cards are part of a collectors edition with features like inserts and a chase aspect, making them highly sought after by sports trading card enthusiasts. This set is a valuable piece of baseball memorabilia for fans of the sport and collectors alike.