Help Identifying Fountain Pen Part

[Bill Bulloch]

I bought my first Fountain Kit, a Traditional from Penn State. Followed the instruction to the letter and the pen came out just fine. The Problem is I had a part left over (always a bad sign). It is not pictured or mentioned in the instructions. Can anyone help me identify it and its purpose? It look somewhat like a syringe with a twist mechanism. The body looks like it might hold a ink cartridge (although it don't seem to come apart).

 

[ed4copies]

That is the alternative to an ink cartridge.

It sucks ink from a bottle.

Attached instead of the cartridge, but the same method.