Recently I bought gladiator shelving system for my 3D printers (mostly Makergear M2) and needed a way to mount filament spools up to 2 KG each. I've heavily redesigned original spool holder by FSU_Innovation_Hub to accommodate this. Single arm is not sufficient for the 2Kg spool weight. I decided that two is better than one and made light version of the arm. Two of these have no issue holding heavy spools and it's actually a lot easier to swap spools on these.
These are mean to be used with 3/4" schedule 40 PVC, but smaller diameter would also work. Included file for PVC caps will prevent them from sliding off.
Use very small infill when printing these (I used 15%) and use PLA + or PETG. Regular PLA is too brittle and might break when attaching. PLA + holds up great.

I've included Fusion 360 files in case you want to modify these.

MK3

Prusa i3

No

No

0.3

15