Since 1883, there have been various systems for filling a fountain pen. Today, ink cartridges are a widespread and popular filling method. In the past, fountain pens were mainly filled using ink bottles. Besides lever fountain pens and eyedroppers, the piston mechanism has been the most important and reliable filling system.

In 1937, the Kaweco Sport fountain pen was first presented as a piston filler under the name #612 and has been further developed in many different versions over the years.

A piston inside the writing instrument allows ink to be drawn directly from the glass into the integrated reservoir. This makes ink cartridges obsolete. The transparent window allows you to keep an eye on the ink level at all times.