Australia 1931 6d Brown Airmail Official Stamp, 'OS' Overprint

Australia · 1931 · 6d

This definitive stamp features the iconic 'Kangaroo and Map' design, a staple of early Australian philately. It is overprinted with the letters 'OS' in black, designating it for official government use. The stamp was specifically intended for airmail correspondence.

Issued during the early years of Australian airmail services, these 'OS' overprinted stamps were used by government departments to facilitate official business by the fastest means available at the time.