Not an Atoma ring
thingiverse
Not an Atoma ring, these Atoma notebook rings are provided with unusual diameters, measured in millimeters, as seen on https://www.cultpens.com/c/q/brands/atoma/atoma-notebook-accessories#:g_brand=atoma&g_category=spare-parts. This design offers brand new odd diameters, still measured in millimeters, that are not officially available. A FreeCAD file is also provided for those who want to create bigger or smaller diameters. It's also possible to purchase the Atoma paper puncher from https://www.cultpens.com/i/q/AM42860/atoma-paper-puncher if you want to make your own notebooks. Note that I have no affiliation with the brand whatsoever. I'll post a maker's guide ASAP.
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