This is a filament clip holder for the matter hackers filament spools ("1.75mm" Filament). This clip holds your filament in place so that it does not unravel and tangle your spool. There are two versions. One version has a "M" engraved on it so that you know which spools use which clips or you can go with the blank no engraving clip.
*** Any of my creations (Mine Only) I can print and send it to you.