I liked the eMaker style feet on their version of the Huxley http://www.thingiverse.com/thing:5631 so much that I had to hack together a matching version for a spool holder.This thing operates on the same principle as other four bearing spool holders and is sized for Makerbot sized filament spools. You will need the following:Assemble as shown, making sure to place a lock washer in between the inside of the foot and the bearing. Inside dimensions are approximately 76mm x 100mm between feet although this is not mission critical. I find it works especially well with 1.75mm filament to feed the filament from the bottom to stop filament unraveling. Enjoy!