I bought a cheap metal-tube spool rack from Amazon and tried to use it as a direct filament dispenser. When I tried to use it, as a spool got low the friction became too much and it killed some prints.

So I designed these to use my MMU roller spools and some spools I had laying around.

They are parametric, so if your metal tubes are different size, or different separation you can download SolveSpace and make that change easily.