Online Pen Company

The Online Pen Company is a German maker of pens and refills. Some of their fountain pens take a standard international in cartridge, while others take a cartridge that has the same shape as the Lamy LT10 and can be used in Lamy fountain pens. Their ballpoint pens normally take a Parker Style G2 refill, but they also offer a number of other ballpoint refills that match common standards. They offer a standard rollerball refill, but their current line of roller pens actually take either of their ink cartridges rather than a rollerball refill.

Manufacturer’s website: Online Pen Company