A donut part that fits into Polymaker spools so they roll smoother on the spool holder
A “lock” part that fits tight onto the spool holder so that the spool doesn't roll off and fall
These parts were made to fit onto my printer (Longer LK1) but could easily be modified to fit other printers and spools.
These parts were made in tinkercad.com
The author marked this model as their own original creation.