C39, CSS AM47a , 1940-41 - Hong Kong Airmails, $2, narrow type, unwatermarked, in block of (25) 5x5, with bottom selvage printer's imprint and plate number BI1.2

C39, CSS AM47a , 1940-41 - Hong Kong Airmails, $2, narrow type, unwatermarked, in block of (25) 5x5, with bottom selvage printer's imprint and plate number BI1.2