Strait Settlements: Sheet of airmail labels

Here is a nice sheet of 45 airmail labels from Strait Settlements!!!

Year: 1.6.1931, Gummed. Günter Mair's catalogue no: - STS-A-4c, rouletted, sheets of 18(3x6) or
54(6x9), 1. line shifted, ref.: "P . & T .-Mail 25", black/greenish grey-blue, 4****