Switzerland: Airmail labels 4

Here i have some more old airmail labels from Switzerland.

Year: 9.1922, Gummed. Günter Mair's catalogue no: - SWI-A-2a, perforated H 11, V strips of 10,
ref.: "No.532.M.S.L. IX.22.-5000.", black/blue-grey, 5*****

Year: 5.1923, Gummed. Günter Mair's catalogue no: - SWI-A-2b, perforated H 11 ½ , V strips of 10,
ref.: "No.532.M.S.L. V.23.5000.", black/light blue-grey, 5*****

Year: 6.1928, Gummed. Günter Mair's catalogue no: - SWI-A-13, imperforated, intended for use on parcels, black/grey-blue, 4****