The Kaweco Mini Converter was designed for the Sport line of fountain pens. This mini converter was specifically designed for the compact body of the Kaweco Sport line, whose reduced length does not allow the use of a conventional converter. It replaces the disposable ink cartridge, allowing you to refill the pen directly from an inkwell and choose from a much wider range of ink colors. It is a preferred option for those who own a Kaweco Sport pen and prefer to refill with bottled ink instead of using disposable cartridges.