Herrick secured the services of a commercial artist, Vance Johnson, with whom Worden discussed the design, resulting in 100 envelopes depicting the phases of the Moon. Worden listed these covers as part of the contents of his PPK for Slayton's approval, along with 44 first day covers that he owned. Ad-Pro Graphics, Inc. of Miami printed the Herrick envelopes, along with card inserts stating the accompanying cover had been carried on Apollo 15. Herrick paid the firm's bill of $50.50; he also obtained the postage stamps for the covers, and two rubber stamps stating the dates of the launch and splashdown. The design was printed on labels that were affixed to the envelopes. Not all Herrick covers are identical, as different cachets, rubber stamp impressions and combinations of postage stamps were used. Worden also carried a cover postmarked in 1928, autographed by aviation pioneer Orville Wright.