Small clip with filter that snap on to spools and holds the end of the filament to prevent it from unraveling.Suitable for most sizes of coils.
Do not remove the clip from the thread when installing the bobbin in the printer
References: https://3dladnik.wixsite.com/workshop/filamentclipfilter
Printed on 3D Printer Lad-1.0: https://3dladnik.wixsite.com/workshop/lad-1-0