This is a knob for the CO2 pressure regulators which are common in Europe. These regulators are often used in homebrew setups where you often have to change the pressure setting on the regulator itself. The original hex-shaped knob is not very handy for changing that quickly.
I know there are other such knobs on Thingyverse already, but I didn't find one that fitted my needs (good feeling when handling and fit on my regulator).
Specifically, I am using this with this regulator: HIWI SK 265-011
The "mm" in the file names is the width of the hexagon, for me the 30mm worked just perfectly. If you need another size, let me know and I can upload that.
Rafts: No
Supports: No
Resolution: 0.15mm layer @ 50mm/s
Infill: 40%
The author hasn't provided the model origin yet.