Summary

A bracket for a filament spool shelf or rack.
I used 3 of them for a 1 meter wide shelf.
I used 2 round wooden broomsticks as carriers. You can used anything with 25 mm diameter or less. I also took 2.5 mm thick steel wires and glued them into the small hole. This makes the plastic bracket much ore stable.

The wall mounting holes have a central to center distance of 85 mm.
Cut out the 2 supporting ribs, that separate the round hole from the slot.
This allows you to screw a regular 3 or 3.5 mm screw into the wall, slide the bracket over the screw heads and just pull them down a bit to get the screws into the slots.