Czechoslovakia: Airmail labels

Here is a lot of early airmail labels from Czechoslovakia.

Year: 1.1928, Gummed. Günter Mair's catalogue no: - CSR-A-5a, perforated 13 ¾ , sheets of 120(6x20), "e" with accent, black/light grey-blue, 4****

Year: 2.1928, Gummed. Günter Mair's catalogue no: - CSR-A-5b, perforated 13 ¾ , sheets of 120(6x20), "e" without accent, further date 1.1930, black/light grey-blue, 4****

Year: 1.1928, Ungummed. Günter Mair's catalogue no: - CSR-A-6a, imperforated (black lines), sheets of 48(6x8), "e" with accent, ref.: "Tiskopis 91 A (I.-1928)", intended for use on parcels,
black/light grey-blue, 5*****

light grey-blue

light grey (unlisted color variety)

Year: 2.1928, Ungummed. Günter Mair's catalogue no: - CSR-A-6b, imperforated (black lines), sheets of 48(6x8), "e" without accent, intended for use on parcels, black/light grey-blue, 5*****

Year: 3.1931, Ungummed. Günter Mair's catalogue no: - CSR-A-7, imperforated, sheets of 48(6x8), intended for use on parcels, black/light grey-blue, 5*****