these are files designed with high accuracy and made for 3d printing with many years of both engineering and printing experience to make sure they are indeed very easily printable and if printed well turn out exactly as the visual model and preview images since all details tips and edges are designed for printability - then exported as a high quality mesh with no meshing issues or hard to mesh geometries as well as parametric files for easy editing free files are nice but they are not quite the same quality standard - same as copypasted comments by people who can read names but don't bother actually looking at the models

Free on Thingiverse