This is an adapter to allow swapping Polymaker 500g cardboard spools with a large center to Bambu reusable spools. Simply tear off one side of the carboard spool, insert adpater inside the cardboard center, insert one side of the bambu spool, flip and tear off the other side of the cardboard spool, insert the other side of the bambu spool, and lock into place. The adapter should be a tight fit and may take some force to install.

I've only had a sample size of one Polymaker PA6-CF 500g spool, so I'm not sure if they all ship with a large center cutout. I only question if that's the case because I was surprised to find someone hadn't already made something similar.

I recommend printing in something that will not deform or melt while drying a high temp filament. I printed mine in ASA.