The holder is currently designed for pens with a radius of 7mm and a round magnet (5mm x 3mm). It fits for most of the typical pens. If not you can change the sizes easily.
Its a fucional tool, because you can attach your pen where ever you need it. For example I have got one on my music stand, to correct my notes quickly if its needed.
You can get creative and use it for other objeckts too.
The author marked this model as their own original creation.