Dry filament is essential to get strong bonds. These desiccant pods sit in the middle of the spool and provide both water-sucking properties and a way to keep the spool weighted in the AMS when it gets down to the very end. However, they don't fit the Sunlu filament spools that we pretty much exclusively use.
The Sunlu filament spools have an internal size of roughly 72mm. These adapters will fit snugly in the spool without to much friction and prevent the dessicant holder itself from rattling around. Simple yet effective. We uploaded the files to Printables so that you too can downlaod and print them if you want.