San Francisco, Cal. Sep 4 1915, International machine with Model Post Office slogan cancel on legal size ad cover with "Read Every Line, then Pass to Some one Interested in California" slogan bearing 2¢ Pan-Pacific (402), tied by unusually clear strike of "San Francisco, Cal / Model Post Office" double-oval (SF15-05) cancel; unsealed to Stratford N.Y. at the third class rate, Very Fine. Bomar Nos. SF15-02  Estimate $300 - 400. THIS IS THE ONLY RECORDED EXAMPLE OF THE 10¢ SPECIAL DELIVERY USED FROM THE PAN-PACIFIC EXPO WITH THE PPIE PERFIN. $0 (Image)