The file 'Clamshell Case 3D Printer Model' is (STL) file type, size is 767.3KB.
Use cylindrical neodymium magnets, 2mm diameter by 5mm height to hold the case closed (the bottom magnets are recessed, and the top ones protrude by a millimeter).
The case needs a flexible filament for the hinge to work. I used PET.