Simple spool adapter rings for spools with large center diameters. Various sizes as I have found the left and right hole dimensions to be inconsistent.
For example, my REPRAPPER spools have measurements on 1 side at 75.5mm and the other at 74.5mm so I made a ring for each side. A small 2mm slit allow you to place it over any filament sticking into the center ring.
The included A1 3MF profile is minimalist and uses only 8g of filament per ring.
Let me know how they work for you and if you have any problems I can fix.