Plastic Adapter End Caps for D1 pen refills to fit twist mechanism in pens.
These end cap adapters slide onto the end of the refill, which you then screw into your pen.
These adapters suit the following pens:
Cartier, Cross, Faber-Castell Multifunction, Lamy M21, Lamy M55, Lamy M70, Monteverde, OHTO Multipen, Parker Multipen/Stylus, Pelikan 38, Rotring Multipen, Swarovski, Swarovski Crystalline, Tombow, Zebra.
Brand: Gutberlet