Planetary gear set-There are 6 external gears and one internal gear. It is called epicyclic gear too. If you want to 3d print the models, suggest to use resin material. If you plan to use ABS/PLA material,it is best to modify the 3d models before printing. Ignore the OBJ and FBX files, they are just for cgtrader's requirement.
More about epicyclic gears: www.tanerxun.com/planetary-gear-system/.html