This cover was sent from the sergeant in charge of personnel at Soc Trang Air Base southeast of Can Tho on 24 November 1953. The fledgling Vietnamese Air Force was still under French command at this time.
The red unit cachet carries the abbreviation "S.P." or Sector Postal in French. A Sector Postal was the equivalent of the American A.P.O. address and had five digits. The number on this cachet has four digits (4304), reflecting the new Vietnamese KBC numbering system.
Note the sender used the abbreviation "KBC" in the return address. Four-digit Sector Postal hand stamps were in use for only a couple of years.