I got a bit tired of having the spool smash around on top of the printer, so decided to move it to the sidewall of the bookcase i have next to the printer instead.
The adapter is to be screwed into the wall to which it is mounted and the spool holder arm from the ender 3 can be slid in from the top.

It has only been tested with the spool holder arm from the Ender 3 V3 KE but my guess is that they are the same as for the Ender 3 and probably also other Ender printers.

Printed in PETG with 0.2mm layers and 30% infill, used support in the holes, but my guess is that it can be left out