Prusa MK3 Spool Holder Clip

A clip to keep spools from sliding horizontally on the MK3's spool holder:
https://github.com/prusa3d/Original-Prusa-i3/blob/MK3/Printed-Parts/stl/Spool-holder.stl
It has two little rounded nubs on the inside to hold it tight.

I know many folks aren't crazy about the over-the-printer spool holder, but it works for me... for now.

Designed in OnShape, based on uploaded Prusa STL:
https://cad.onshape.com/documents/add2b674a1c0460683fa84e8/w/afe1410dd3f6c6efa0dec4d2/e/99fabe66fd4ec89af2a3ec