1879, 6¢ pink, horizontal pair. Well centered, minor perf flaws in left stamp, tied by "New-York, Jul 23 '80" duplex cds on cover to Sydney, Australia at the 12¢ treaty rate, reverse with magenta San Francisco and Sydney datestamps, Very Fine; with 2008 P.F. certificate. Scott No. 186  Estimate $200 - 300. $0 (Image)