Hi. This is a dowel / rod that fits perfectly with Tauron's Filament Rack: https://makerworld.com/en/models/461746

It fits perfectly snug in the holes in Tauron's design, and it fits 3 spools exactly. It's great for small spaces if you don't have a ton of spools.

Because this is 3D printable, I recommend using something like PETG, and my .3mf file is perfectly sturdy with 3 walls and 30% cubic infill. That's all you need.