This is a 3D-printable planetary gear system designed for easy assembly and smooth operation. The model features three planet gears, a sun gear, and an internal ring gear, all held together by a central carrier. All parts are optimized for printing without supports and fit well with standard 3D printer tolerances. You may have to adjust the gearing clearence for your printer to assure smooth rotation. Perfect for educational demonstrations, mechanical projects, or as a fidget toy, this gear set demonstrates the fascinating motion and mechanics of planetary gearing systems. This version uses 685ZZ bearings (5mmx11mmx5mm) but they can be replaced with printed sleeves if needed.