Yes, I am aware of Watermans, and even Pilots writing better. But I also happened to find the rare Fisher space pen refills that were made for Montblancs, and man they work well! I also found the pen quite inexpensively. Admittedly, my friends know me as a techno-whore, but I am very fond of my Filofax. There’s something quite grand about writing out your day, schedules, and addresses in the real world. I’m not a GTD freak— I just like to jot some to-dos and appointments. And yes, I do sync the iPhone, because I will forget anything and everything.
It disturbed me that the Filofax pen loop diameter really only fits thin pens and their own slim pen, which I have since thrown out. It’s also odd that you can’t find any information. For the record, Lamy Safari pens won’t fit either.
I thought about it for awhile, and tried to figure out a way to get this nice pen to fit. I dug around my desk drawer and found:
- a uniball vision pen
- a long, wooden golf tee
No, I’m not much of a golfer. If golfing means getting the lowest score, then the only way I can accomplish that is by not playing.
Simply, I stuck the uniball pen in the loop (which fits very well, albeit a tad tighter than slimmer pens), and plied the golf tee underneath. I then let the stretching duo sit overnight.

The result: a perfect fit for the Montblanc. Slides in and out easily, but lots of tension to keep the pen secure.

Yes, the pen does hang a bit out over the top edge, but it fits well, and is plenty compact enough for portability, using the Pocket-size Filofax. Additionally, a U.S. Passport fits snugly in this version of the Filofax.
Happy writing!