Edit: Also try my version with diamond knurling. In case you have both, please comment what version you prefer.

This is probably my best fidget toy! I printed dozens of them because people asked for them.

It's a small, but satisfying fidget toy. You'll probably not want to wear it all the day due to it's size, but it's unobtrusive enough so you can still do a lot of things while wearing it. But while wearing it, you have a fidget thing right at hand for some quick fidgeting. (I'm wearing one as I type this; and fidgeting with it when thinking about what to type next.)

Also the planet gears look like plus signs - for some positive influence :) and they look quite a bit mesmerizing when moving in perfect unison.

I uploaded 4 sizes, 14mm, 16mm, 18mm and 20mm. If you need another size, ask in the comments and there's a good chance I'll make that.

You might need to use a bit of force to break the gear loose at first, but after a bit of breaking in it is supposed to run quite smoothly.

Happy fidgeting!

Update: Added a 22mm version as STL (Download or Print → Download STL)