The standard pearl black converter with chrome elements fits into most Kaweco fountain pens. Instead of two ink cartridges, the converter is inserted into the barrel of the fountain pen.
This makes it easy to fill up with ink from the ink jar. drawing up the ink multiple times increases the filling quantity.
A big advantage of converters is, above all, the sustainability aspect:
In contrast to conventional ink cartridges, which end up in the trash after the ink has been used, it can be permanently reused and refilled again and again.