Kaweco mini plunger converter is designed for Kaweco Sport fountain pens. Allows the use of bottled inks with many compact fountain pens that can normally only use short international standard cartridges. Will fit almost any pen that uses international standard cartridges. Technically, it does fit the Kaweco Liliput as long as the plunger is not fully extended. Use a short international cartridge to achieve maximum ink capacity with the Liliput.