This model is a remix of https://www.thingiverse.com/thing:5476430. Unfortunately, the model is no longer available there, but I have loaded it with the CC BY License. Thanks to https://www.thingiverse.com/sirlenin/designs for the original design! In the meantime it is also available here https://cults3d.com/en/3d-model/tool/co2-cartridge-tool-container-for-bike-fork

I only slightly adjusted the dimensions of the model so that it fits well in my Trek Procaliber 9.5 with the RockShox Judy SL fork, which seems to have a slightly larger diameter (even though the specification also says 30mm...).

All parts should be printed with TPU. I recommend the version with O-ring.
In addition to a 16g CO2 cartridge, you also need a suitable valve, I used https://www.topeak.com/global/en/product/1420-NANO-AIRBOOSTER, which fits Presta and Schrader valves. An M6 nut and bolt are also required for fastening. For details I refer again to the original https://cults3d.com/en/3d-model/tool/co2-cartridge-tool-container-for-bike-fork