The O 10000 was used in the 1930th as an urban bus and long-distance coach and impressed people by its very size.
The vehicle on show served with the Austrian Postal Service as a parcel truck after World War II on the Salzburg-Vienna route.
Later on, it was converted into a mobile post office and was used at events like the Salzburg Festival or as a temporary post office.

6-cylinders, 11,197cc, 150-horsepower @ 1,700 RPM, 65 km/h top speed