The top part has a 5mm thread (adjusted towards 4mm), you can screw in the bowden tube, and it's pretty tight. No need for a pneumatic connector like other designs.
Inside, you can squeeze in a piece of sponge to clean the filament before it reaches the printer.
The hole you need to make in the box has a diameter of 14mm
Import in slicer and split to objects.
Print the top part upside down.
Prints without supports