Cape of Good Hope 1865 4d Steel Blue Triangle on Letter

1865 De La Rue 4d STEEL BLUE triangular (SG 19c) on folded entire from the te Water correspondence. Cape Town to Graaff Reinet, the adhesive with full margins superbly tied by BONC 1 with duplex cds FE 24. Front shows the arrival oval FE 27 in red. Couple small imperfections, a scarce use of this elusive shade on cover.