This is a spool holder that can hold five different 1kg spools at the same time (It could hold more smaller spools). It is perfect for the Prusa Multi Material Upgrade, as it can hold as many spools as can be used.It also works for just storage, as it can hold many spools. The spool holder easily comes apart and allows you to slide the spools on. When the spools run out, take apart the assembly, slide the spools off, and put new ones on. I would reccomend printing this with supports coming from the build plate, but not anywhere past that. Make sure that all debris after printing is cleared out of the holes in the centerpeice, or else the side pieces will not slide in.
The file that says spool holder left is actually for both sides.