Stem cap and the filler are made of metal, but are covered with a transparent plastic. Advantage: The'll probably look even so bare in 10 years as new. Disadvantage: It has just "take in hand" when a plastic feeling. My conclusion: I take the plastic feeling into account, especially since you can hardly see the plastic coating. For this, the part is just very sensitive to hand perspiration, scratches etc. Otherwise, the a metal filler for people (like me) who like `what in your hand when writing shall be called: the filler is relatively heavy and thick. My copy has a wide line width and a strong ink flow. The (Pelican) ink cartridges are felt quite quickly empty and I plan on a converter convert, especially since the selection is greater in less ink and will make me the "Rumgetüddel" with the converter fun. According to the motto: If already filler, then right ;-).