This is a simple filament clip to prevent filament on the roll from unwrapping. It's actually quite strong and holds well. The extra ring is for easier grip. This object is fully customizable but default values give a decent clip. Standard for 2.85mm but changeable to 1.75 with the customizer.

This thing is inspired by intofocus' http://www.thingiverse.com/thing:282242. Because this clip is a lot smaller (to stay flexible) the handle is nice, to have good grip.