It is model or planetary gearset

Speed ratio = 6

Hold one hander in left hand and rotate other handler with right hand - cented part will rotate fast

I print it with:

• 3 loops
• Concentic bottom and top surfaces
• 20% 3d honeycomb (for better mass centering)
• No support
• No brims

But probably it can be printed with default parameters

You need few drops of cianacraillate glue to assemble it