Wall-mounts for white/chalk/other boards, different sizes

A friend needed to mount a second-hand whiteboard but missed the mounting-hooks. So this is a simple design based on a "commercial" one which I had laying around.
Because i was already busy with it, I created a few other hooks for other board thicknesses. I added the stl's for 08 - 24 mm thick boards. Except for the width of the hook they are the same.

Edit: added two more extra sizes for mirrors and such, 3.5 mm and 4.5 mm.

The edges on the back are rounded to prevent scratching while mo