1945 Guštanj porto provisorium, official letter sent from Ljubljana (28.8.45) to Guštanj with arrival postage due stamps (30 pf Maribor local provisional issue and 0,50 din regular DFJ issue) cancelled with "Guštanj," / "PORTO".
Note that "Guštanj," ends with a comma. This is because it was used as a prefix for other cancellers, usually for "PORTO".