Powerball - gyroscopic exercise tool

This is a model of a gyroscopic exercise tool (a device sometimes used to exercise the wrist in physical therapy).

The exact product which is modeled is the original powerball, however as this is my first 3d model ever, it is indeed imperfect and incorrectly modeled.

The model has been created in OpenSCAD, and feedback / improvements, alike is indeed welcome!

While it's unlikely that the device will actually be functional (most likely due to excessive friction), is should be noted, that