The piston fillers M464, M465, M475, M480, M484, M485, M486, M488, M491, M490 and M495 were sold in the mid 1960's in Japan.
All these models can be operated with cartridges or converter.
However, the shapes are very similar to the piston fillers which were sold in this period in Europe.
Surprisingly, the model numbers all begin with M (= mechanics), which is usually used for piston filler,
while P was used for cartridge fillers.
We presume the reason for this type of numbering was that these were fitted with a converter by Pelikan.
On top of the Cap engraved – Pelikan logo
For more details please see the photos,
They are part of the description.