Rexpen Diplomat
Rexpen was a sub-brand of TOZ Penkala which was founded in 1936 in Zagreb. (TOZ stands for Tvornica olovaka Zagreb, or “Pen Factory Zagreb”) This brand was so popular in Croatia that, today, a fountain pen is usually called a “penkala” (in the same way that Americans and Canadians ask for a kleenex instead of a tissue, or to go make a xerox instead of a photocopy).
This pen was made in the 1980s and was likely given as a corporate gift (according to the knowledgable guy I bought it from in a pawn shop in Split).
See also this mechanical pencil from Croatia.
V2023024