I started to use filaments from new source: http://www.eco3dfilament.com and I wanted to make the reduction for the spools as well. So I remixed my original Prusa filament spool reduction. Reduction_ECO_big_hole.stl is for 0.25kg filament spool. Reduction_ECO_small_hole.stl is for 1 kg filament spool. Btw, check them out if you want. They make good filaments. While I was into it I added universal Scad file for your convenience. You just edit three basic variables and produce your own different size spool reduction. Variables are: Diameter of the spool hole. Width of the rim in spool hole. Diameter of spindle of spool holder. and thats it.