San Francisco, Cal/M.P.O. Oval cancel (Bomar SF15-05A) on 1915 registered cover to Ohio with rare violet double circle "San Francisco Model Post Office Sta., Cal./Registered " (Bomar SF-15-06) backstamp, franked with 2¢ + 5¢ Pan-Pacific in combination 5¢ Jamestown, cover opened for display, Very Fine and attractive. Estimate  $500 - 750. In addition to this newly recorded cover, three other examples of this cancel are known. One used as a back stamp on a cover mailed from the Model Post Office, another as a favor cancel on post card along with Bomar SF15-01 and the last is on an undated cover used as a parcel label from the Japanese Tourist Bureau to mail exposition promotional material.One of the most spectacular covers from this Exposition and the only example of this rare marking used properly on a full cover. . $0 (Image)

San Francisco, Cal/M.P.O. (Model Post Office). Oval handstamp (Bomar SF15-05A) on reverse of 2¢ Postal entire postmarked with San Francisco Panama-Pacific/Apr. 10, 1915 machine cancel slogan cancel to Denver, Very Fine and rare, one of three recorded examples of this rare Expo. marking, one is known as a favor cancel, one is known on a label & this example. Estimate  $500 - 750. $0 (Image)