Spacer for BuMat Filament Spools

This is a spool spacer for the BuMat brand. It has a 57 mm external diameter and a 21 mm inside diameter. Fits like a glove... or a spacer in a spool... you get the idea!

Try it out with my spool holder for the Printrbot! http://www.thingiverse.com/thing:415587