Not long ago, I needed a pen-sized box from AlmisuifreMinimalist pen case with a buckleIt left a deep impression on me. Recently, I needed a box again and hoped to have one with a similar style, so I created a model along similar lines, but it can be configured to any size. The model is included, so it will run in the Makerworld customizer. I made two changes: one is to make the side grooves deeper to achieve a stronger texture effect; the other is to make the button protrusions stronger. I think I might modify it at some point because it's a bit tricky. If you encounter problems, gently polishing it might help.

The minimum width is about 25 millimeters. Although it can be smaller, it might not be as useful at this size.