Neat collection of signed "Centennial of Baseball" stamped and postmarked "significant event" envelopes. 6 1/2" x 3 5/8" in size and are Mint condition with bold signatures and inscriptions. Includes Harvey Haddix 12 Perfect Innings, Johnny Vander Meer back to back no-hitters, Bill Wambsganss unassisted triple play, Elmer Smith 1920 World Series grand slam and Rube Marquard 19 straight wins. They all come with individual COA's from PSA/DNA.