1a carmine EVII issue used with superb complete strike of CAMP P.O. No. 4 cds dated 15 MAY 1905 of the Seistan Arbitration Commission which was established to demarcate the boundary between Persia and Afghanistan in the vicinity of Seistan. The Camp Post Office served the commission using this cancellation between February 1903 and June 1905. Very rare, less than ten examples are known. (SG 123)