Shelf holders: for standard metal pin or with screw

If printed on the largest face no supports needed (the screwed model can be printed w/o support with the screw hole vertical position as well).

I used 100% infill for strength.

The sleeve model works with the standard cheap 5mm shelf pins (see on the pic.).

The screwed model works with 4x25 wood screws (in 18mm thick material). (10mm of the screw length stays in the holder.)