borgmann.williamAccording to various items I've read, the piston converter does not fit the metal Sports well. From the Goulet Pens website: "This small piston Kaweco converter will fit in all Kaweco plastic pens (the Classic Sport, ICE Sport, and Skyline Sport), allowing you to easily use bottled ink instead of ink cartridges. It does not fully fit into the metal Sport pens (AL, Brass, etc) or the Liliput." That said, for me personally this is the kind of casual-use pen with which I'm perfectly okay using the cartridges. If I really wanted to use one of my favorite bottled inks with this pen, I think I would try using a syringe to fill a used cartridge.