Uni-ball SXR to UMR Refill Adapter

The Uni-ball Jetstream SXR refill is about a millimeter shorter than a Uni-ball One SXR refill, so swapping these refills, I noticed two problems:

• The nib sat slightly more recessed and so its taper did not align with the pen body's tip curvature
• The knock mechanism was slightly lighter and more prone to inadvertently deploying in my pocket

This adaptor solves both problem, while preserving an air vent for the ink.

If it prints too loose or too tight, you can adjust either the extrusion multiplier or scale the part a few percent. Though if the adapter is just slightly too tight, you should be able to friction fit it by pushing hard against your desk.

Any filament material should work fine.