Bowden coupling spacers, designed to fit the E3D embedded and threaded couplings. It can probably be resized to fit other connectors. With the threaded connectors, instead of using one of these, I prefer to preload it by screwing in the coupling with the PTFE tube sticking out slightly (with filament loaded).
Remember to come back and post what you've printed as Make.
It's good for the designer and the community (that means you)!
To post a Make, come back to this Thing and click Post a Make.
Or, you can use the Thingiverse Mobile app found on
and the Apple App Store.