Concealed fixing hanger / hook

This is a concealed fixing wall hanger.

Simply screw the bracket to the wall using a small counter sunk screw .The base has to go the right way up - there is a recess in the square cutout on the top side.

Insert the hook into the hole angled down slightly as in the diagram, and press down until there is a click.

I Printed at 45% infill with 3 perimeters and 3 top and bottom layers in PLA.
the higher the infill the stronger it should be ,but i haven't tried it yet to see if the hook w