This is my take on the desiccant / humidity sensor holder that fits Bambu Lab's Spool, as well as all the remixes and derivatives that are out there. This will also fit most 1kg filament spools from other manufacturers, such as AMZ3D, Sunlu, and many others.

The low-profile nature of this design allows it to be used with many storage methods, such as zip-lock backs or vacuum-sealed containers.

This model fits the standard hygrometer that can be found on Amazon or AliExpress, I used this one in particular.

After printing, simply insert the humidity sensor into the top, fill the bottom with your desiccant beads of choice, and insert into the middle of your filament spool. Screw the lid into place until snug, and store!