This filament clip is specifically designed to securely hold Sunlu filaments on the spool when not in use, taking advantage of the raised ridge band around the sunlu spools. It can also be used on Inland reusable spools for their spooless filaments. It has a low profile, a minimalist design look, and is simple to use: snap it on the spool and clip on the filament.
It's designed to have a snug fit to prevent the clip or filament from getting off, a problem for some other clips. When putting it on or taking it off, it can be easier to start from the side that's on the outer side of the spool.
Disclaimer: The word “Sunlu” on the clip is only for labeling purpose, indicating the clip is for use on Sunlu spools. It does not indicate or imply this clip design is endorsed by Sunlu.