I’ve been using the Supernote refill in the Kaweco Al Sport rollerball (with the grip/tip from the Kaweco Classic Rollerball…because it’s plastic) and also the Faber Castell Hexo rollerball for a few months and absolutely love both of them. I have the best of these premium pens with the feel and longevity of the Supernote never replace ceramic nib. In my opinion, these are the perfect combo for the perfect EMR pens. Especially the Kaweco Al Sport because it’s the perfect weight and length.
Other reviews had said that the Kaweco classic rollerball and the Kaweco Al Sport couldn’t be combined because the threads are different, which is true, but the classic is plastic and therefore malleable. I added 2 wraps of plumbers tape (for pipes) to the classic’s threads and it fits perfectly. You have to go slowly (tighten and loosen several times before it goes all the way in) and it will feel like you’re forcing it, but it works. Then you add 2 wraps of the plumbers pipe tape after for security and it fits well and isn’t wobbly in the least. I’ve made 6 of them this way and they are all secure and a tight fit. They look like they were made that way. The Supernote refill is also the perfect length for the Kaweco Al Sport and Kaweco Classic combo. No modifications of the SN refill are necessary. You just pop it in and it’s ready to use.