Planetary gear set-type 1, including 1 sun gear, 3 planetary gear, 1 ring gear, and some other parts. Parts are designed for 3d printing or laser cutting. Ignore the FBX and OBJ format files. They are just used to meet the platform's requirement. For 3d printing, STL format files are ok; For laser cutting, DXF files are ok. More: https://www.tanerxun.com/planetary-gear-system/.html