C36, CSS AM44a, 1940-41 - Hong Kong Airmails, 60c, narrow type in block of 25 (5x5) with printer's imprint and plate number BF1.2

C36, CSS AM44a, 1940-41 - Hong Kong Airmails, 60c, narrow type in block of 25 (5x5) with printer's imprint and plate number BF1.2