A roller that fits inside of a filament spool. Though this roller is designed to fit inside of the spool holder for Tomson's MiniBear mod, it works with any mounting system with a hole diameter of 25mm. The adapter pieces are sized to fit a spool of hatchbox filament. More adapter sizes will be added in the future, this is a WIP.

STL file contains all parts necessary for assembly minus two skateboard bearings. Separate into objects in the slicer of your choice. 

Link to Tomson's MiniBear project where you can download the rest of the files, including the spool holder for this spool: https://www.printables.com/model/68537-mini-bear-remix-and-spoolholder-and-filament-feede