These are labeled caps for the Embedded Magnet Dispenser Tool by Brian Dean (https://makerworld.com/en/models/60890#profileId-63102) that keep the magnets securely inside the barrel of the dispenser. These were only tested on the magnetic dispensers printed in PETG, but should fit models printed in other materials as long as you are using the print profiles included with the original model.

I tested the caps printed in Bambu Lab PLA Basic filament and intentionally made them a tight fit to account for wear caused by frequent use. I recommend rotating the cap while installing/removing it to make the process easier. If you find that the fit is too tight for your preference, then scale the object up by 1-2%. I added a beveled edge to make the initial insertion even easier. The diameter of the barrel is engraved on each cap to allow for simple color painting in Bambu Studio using the fill tool.

There are two print profiles: one for dual color and one for single color prints. Each profile contains a plate with 2 caps for a particular diameter and then one plate with a set of all 9 diameters for the most efficient print (especially if using dual colors).