This is a quick fit filament oiler for when you are printing PLA on an all metal hotend. It is split for easy fitting with printed hinges and is held together with an elastic band.
Fit some sponge or cloth, add a few drops of cooking oil, close over your filament and secure with an elastic band.
The print in the photo is a bit rough as this printer needs a bit of work.
You can also use this as a filament cleaner/filter if you don't add any oil!