Sudan: Airmail labels 3

Here are few of the early airmail labels issued in Sudan.

Year: 1931, Gummed. Günter Mair's catalogue no: - SUD-A-1, perforated 11 ½ , sheets, 
black/greenish blue or blue/white, 4****

blue

greenish blue

 Year: 1931, Gummed. Günter Mair's catalogue no: - SUD-A-2, perforated 11 ½ , sheets of 20(5x4) 
or 20(4x5) or 50(5x10), black/blue or light blue/white, 4****

blue

light blue