Pen O-Pen

Pen O-Pen is a simple but effective pen. It has a special trick: Normal pens are usually designed for one type of refill. Pen O-Pen connects to alle available refills. It is easy to produce and customise. Trikka added No 3 out of 6 open design pens made by the designer Lars Zimmermann.

Currently available 


This pen can hold different kinds of refills. Lock them in place with a set screw.
Aluminium engraved.
The same solution using different materials
A piece of silicone tube…
This is No3 of Mifactori open design pens.
added as cap.

Extended info

  • “It happened to most of us: Our favourite ball point pen is suddenly out of ink. We search for another ball point pen to swap the refill. Only to discover: the refills are different. The new one does not fit. Well if PenOpen is your favourite pen this won’t happen again.”
  • Above you can see a picture where a cap is added. The cap is just a small piece of silicone tube. The cap is not part of Trikkas parts catalog. 
  • Please visit the original post by the designer to learn more about Penopen and how to make it and to see iterations of it. 
  • Pictures by Mifactori, CC-BY-4.0
  • Disclaimer, initial post backup.pdf