EPICYCLIC (SUN AND PLANETARY) GEAR
The model contains STL files for Epicyclic gear mounted over NEMA-17 stepper motor. The planetary gears have 623ZZ bearings inside and are mounted on 3mm dowel pins.
The output shaft is M6 hex bolt secured with a nut.
All securing screws are M3 bolts which get attached to the object using M3 threaded inserts.
For any other required details pls put it in comments.