Single Hex with Pen Clip.

Simple Remix.      I needed a replaceable pen holder for my whiteboard after my first attempt broke.     Basically chopped up and merged several files.     Single Hex with an empty insert.  Then my original design with the Hook.      In the future, if the pen attachment breaks, It will be a few minutes to replace it !

Edit

Realised I uploaded the wrong model.

I merged a single Hex with a Hallow Incert.  Then Chopped the incert off a shelf and used it as the bases for attaching a pen clip.