The Spanish company BJC (https://www.bjc.es) discontinued the production of their widespread old socket outlets years ago. As the outlet covers are no longer available I created a fitting look-alike. 

It has to be printed vertically. However, not all slicers will be able to generate suitable supports. I am therefore including the necessary support structure in the design. The support will have to be removed with a sharp knife after printing.

As always I include the OpenSCAD source file for you to adapt and/or improve:

• Download and install OpenSCAD from https://www.openscad.org
• Launch OpenSCAD and open the enclosed OpenSCAD source file (/File/Open).
• Amend the parameters at the top of the file or even amend the code.
• Save your changes (/File/Save).
• Render the design (/Design/Render).
• Export the rendered design e.g. as a .stl file (/File/Export/Export as STL).
• Slice and print.

See my other designs at
https://www.thingiverse.com/thinger13/designs