Tanga Prepaid Franking
German East Africa
On 18 January 1916, a new system was introduced to reduced the usage of postage stamps, which were in short supply due to WWI.
Envelopes could be sent to Morogoro, Dar-es-Salaam, or Tanga to receive a prepaid franking mark. The mark consisted of the value and the official seal of the post office.
The envelopes could then be used at any local post office.