There are 3 parts to the print, the stand, the rocket main body, and the nozzle.
I used two 13mm diameter steel bearing ball and a 15mm diameter by 2mm thickness magnet. You only need one steel ball for it to work.
I added more spinning bodies here: https://www.printables.com/model/484455-ball-bearing-spinning-toy
The author marked this model as their own original creation.