Noodler's Ink - 4.5 oz Eye Dropper System - Eyedropper Pen Replacement O-Ring - Pack of 10

Converting a standard fountain pen into an eye dropper pen is a favorite project among fountain pen aficionados. It involves filling the fountain pen body with ink (rather than a cartridge) and closing it with a tight seal through the use of an o-ring. You can find out more about how to convert a pen into an eye dropper pen from our PenPedia article: How to Do an Eye Dropper Pen Conversion.