Thanks for your response!
The diameter of the pen is 10.5mm so I think it may not fit after allI just cannot live without my erasable pens! They are such game changers.
Guess I just have to live with those ugly plastic frixion slim pens![]()
I have took couple of photos for different pens, the pink one is just a standard gel ink pen from Muji, it fits in comfortably, but need a little bit of force to insert it in, the black pen is slimmer, slides in smoothly. hope it helps.

