The Kaweco Perkeo Roller, in green, is the gel ink rollerball version of this larger Kaweco pen. This gel ink rollerball version from Perkeo maintains the larger body of the Sport (13.9cm closed and 15.7cm with the cap attached) and the snap-cap closure, eliminating the need for screw threads. The gel ink flows more smoothly than a conventional ballpoint pen, producing a more uniform and quick-drying line. It's a prime option for those looking for a larger rollerball pen in this color.