ultramarine oval handstamp on 1861 folded letter from St. Leonard, Maryland to San Francisco, black "Pony Express, The Central Overland California & Pikes Peak Express Company, Aug 18, St. Joseph, Mo." oval-inside-circle handstamp, two 1860 5c Brown (30A) singles tied by black "St. Joseph Mo. Aug 16" datestamp, right stamp with pulled perforation nick at bottom (mentioned on certificate although we feel strongly that it does not detract from this extraordinary cover), very fine and attractive, the only known Pony Express cover with the 5c Jefferson issue, 2022 Philatelic Foundation certificate, Frajola-Walske-Kramer census #W49