This, rather pretty, leaflet describes the Itallia derailleur.

I am at least two minds about the date of this contraption. This leaflet, with spot colour and photography, looks slightly post-Second World War. However, my hunch is that, with that huge lever and those rods, this derailleur design is seriously pre-Second World War. My least-worst guess is 1939.

• Publisher: Itallia
• Country: France
• Date: 1939?
• Derailleur brands: Itallia
• Derailleurs: Itallia