Designed for Bambu Lab Spool - https://wiki.bambulab.com/en/knowledge-sharing/Links-to-STL-models
Tested on Polyterra and Overture cardboard rolls, I cannot guarantee fitment for all cardboard rolls.
This creates a tight fit between the plastic spool and the carboard insert as well as keeps it centered so that it doesn't jerk as much while pulling in through the AMS.