Filament blender for aluminium extrusion profile

All credit goes to Make Anything for giving me this idea, his video on the topic can be found here: 

furthermore, his free STL files to his original version can be found here: https://www.myminifactory.com/object/3d-print-138353 or in the description of his video.

My version does the exact same thing: it colors filament (ideally transparent or white) before it goes into the extruder, but it fits into an aluminium extrusion, commonly used to create the frame for a 3d printer. I use mine on my creality CR-X which has bowden extruders and aluminium extrusions as a frame.  It is designed to fit 2 sharpies or permanent markers, use a rubber band to push the sharpies onto the filament and improve the result a little bit.