1969 "Centennial of Baseball" first-day cover signed by the following eight Hall of Fame players: Joe DiMaggio, Sandy Koufax, Lefty Grove, Rube Marquard, Jesse Haines, Cool Papa Bell, Burleigh Grimes, and Lou Boudreau. (The signatures of Red Faber and Joe Cronin have been deemed secretarial examples by PSA.) The signatures, scripted in a variety of inks, grade 8/10 overall. The envelope (6.5x3.5") displays ten small numbers written in pencil on the reverse and is otherwise in Excellent condition. Full LOA from PSA.