I have a GEEETech i3 3D-printer. Works like a charm but the filament holder that came with it does not work properly. Another issue is that majority of filament rolls available to me locally are Robox CEL rolls which have a different layout than the ones GEEETech is shipping out.
So, in order not to order rolls from China and wait several weeks for them to arrive I decided to go with the Robox filament rolls. And to prevent the need of manually rotating the rolls to ensure that enough filament is available to the 3D-printer, I designed a wall mount stud.