Germany: Zeppelin airmail labels

Here are rare labels from Germany. It was intended for use on Zeppelin-mail. Issued by S.E. Sieger, stamp dealer at Lorch.

Year: 1932, Gummed. Günter Mair's catalogue no: GER-C-15a, perforated 10 ¼, sheets of 20(2x10)
intended for use on Zeppelin-mail, blue/white, 5*****

Year: 4.1933, Gummed. Günter Mair's catalogue no: GER-C-16a, perforated 11 ¼ , sheets of 10(2x5),
intended for use on Zeppelin-mail, blue/white, 5*****

Year: 4.1933, Gummed. Günter Mair's catalogue no: GER-C-16c, perforated 10, sheets of 10(2x5),
intended for use on Zeppelin-mail, blue/white, 5*****