The Kaweco Mini Fountain Pen Converter is designed for the Kaweco Sport fountain pens. This converter can be used with other small barrel fountain pens. The converter has a plunger fill system that measures 1 3/8” when compressed and 2” when drawn out. Holds only 0.5 ml of ink capacity. This converter is not compatible with the Kaweco Lilliput, earlier AL Sport, and AC sport fountain pens because they are not deep enough and some of the ink is pressed out of the filled converters again while the barrel is being screwed onto the mouthpiece. Included is one Kaweco mini fountain pen converter.