There are those who might be new to fine writing instruments and may not be comfortable yet with fountain pens and want a more familiar Rollerball option. There are also those who know and love their Fountain pens but they wish to have the ability to have a Rollerball for those jobs best suited.

The Schmidt® Cartridge-Rollerball system is an ideal answer to either of the above as it allows for you to take advantage of the 100s of available Fountain Pen inks, either using cartridge, converter or eyedropper methods. Available in 0.5 (fine) or 0.7 (medium) in black or chrome.

If you want any Mercury Pen with the Rollerball option as the primary or for $6 additional you can have a swapable section for the rollerball.

If you want an IKE or Liberty Model (with #6 Bock nib) you can also add the LHC Rollerball Adapter for just $25 (includes Rollerball nib)

If you want the Freedom model with the rollerball option you can add that at checkout for that pen or order separately here: Freedom Rollerball Conversion.

https://www.schmidttechnology.de/en/products/writing-instruments-technology-2/fountain-pen-technology-cartridge-rollerball-system/#1536819795380-29dd887f-ca8c