Here is a complete booklet with 10 vertical strips issued by K.L.M airlines. Also booklets come with 16 vertical strips of 4.
Year: 1935, Gummed. Günter Mair's catalogue no: - NEL-B-4, rouletted H, booklets with 10 or 16
strips of 4, issued for customers in Egypt, blue or dark blue/white, 4****