Tanger, air mail overprints, key values of the 1938 issue

Key values of the 1938 issue: 50c, 60c, 1p, 4p, 10p. 50 & 60c (Edifil 136 & 137) with color change on the overprint, 1p with red and black overprints (Edifil 138 & 138hcc), 4p with regular and inverted overprint (Edifil 139 & 139hi) and 10p Edifil 140. All MNH except 4p Edifil 139 & 1p Edifil 138hc, that are MH. Genunine overprints with a catalogue value of 1,000 €.