Here's the source coupling modified to be a perfect fit with any Elegoo Saturn printer that has the built in fume extraction port. This part is to be used with V3 of the Fume Extraction system.

v3 Fume Extraction System: https://makerworld.com/en/models/487870

Note: This STL file has a 0.2mm tolerance built in. If you need to adjust the tolerance then you must download the F3D file and update the tolerance parameter. Instructions on how to do this can be found HERE.