In 1939-1940, certain values (MiNr. 512, 513, 515) of the December 1933 Hindenburg Medallion
issues were available for purchase from vending machine in short, 10 Pf “donor strips” (Einheitsgeberstreifen, or EG-Str.). The three varieties of strips first became available in 1939 (EG-Str. 1) and 1940 (EG-Str. 2-3).
These strips were dispensed in envelopes which bore advertising from various sources, and also included postcards with additional advertising. The advertiser paid a fee of 4.50 Marks per 1,000 envelopes/postcards, with minimums of 30-100,000 copies.
The strips were printed in sheets (Einheitsgeberbogen, or EGB) of 100 (20 strips), which were available for purchase from the philatelic sales window at many post offices. Several variations exist.