These stamps were issued on 8 April 1928 to commemorate the Anschluß, or unification of Austria and Germany.

Though very similar in appearance, there are minor differences due to the use of different printing offices:

MiNr. 662 – Government Printing Office in Berlin
Swastika watermark
Image size – 23 x 28mm
Perf K 14

MiNr. 663 – Government Printing Office in Vienna
No watermark
Image size – 21.5 x 26mm
Perf K 12 3/4
Engraver’s mark “E.P.” to left of foot at lower left