Switzerland
1923 MiNr. CH 184 in different colors, with black overprint. Only used for special post flight on 22-5-1938. Mint stamps are rare
| Country: | Switzerland |
| Type: | Postage stamps |
| Series: | Pro Aero |
| Nominal: | 75 Ct. |
| Year: | 1938 |
| Perforation: | comb 11½ |
| Mintage: | 287,502 |
Pro Aero
