(1915 Pan-Pacific Exposition) San Francisco, Cal./Model Post Office. Oval cancels (Bomar SF15-05) tying Pan-Pacific 10¢ orange, perf 12 + 2¢ carmine, perf 10, three singles each with perfins "PPI ECo" (Panama-Pacific International Exposition Co.) on registered cover to New York, backstamped with two strikes of violet "San Francisco (Model Post Office Sta.) Cal./Jun 12, 1915/Registered" double circle handstamp (Bomar SF15-06), cover with "Department of Official Coins and Medals Service Building" corner card; partial backflap, Very Fine and rare, these covers were used to deliver Pan-Pacific Commemorative Coins. Scott No. 400A+402  Estimate $150 - 200. $0 (Image)