Rollerball Refills by Schmidt
Schmidt 5888 Metal Rollerball Pen Refills
The Schmidt 5888, also known as the 888 refill, is made in Germany using the highest quality ink and parts. These will fit many pens that will take a "standard international" sized rollerball refill. Please be sure to measure and look at the shape of you current refill to be sure these will fit your pen.
These will not fit brands like Cross, Waterman, Parker and a few others.