This spool holder is intended to be somewhat air tight to prevent moisture absorption. The spool holder itself is this one which uses bearings and has a nice size plate on the mounting end. This helps with the seal on the case.

The original version of this was printed with clear filament in vase mode. This worked for a while, but I found the vase mode to not be strong enough and the edge of the cover broke off. So this version is made to print in normal mode and with stronger walls.

The cover has some flat spots on the sides. The one on the bottom can hold a desiccant bag. The one on the side is to allow mounting a Bowden tube coupler. This coupler works pretty well. The backing plate provided will allow you to sandwich the spool cover between the coupler and the backing plate. Use some M3 screws and nuts to put it together.

There are also a few window openings so you can see how much filament is left on the spool. The one pictured has only one window, but I added a couple more. You need to let some light in so you can see better. I haven't printed this version yet. I used some clear acrylic from Home Depot for the windows. Cut them to 42mm squares and seal them in with clear silicone.

The outer cover just slides snugly over the base. Mine fit pretty tight and I needed to sand the inner edge of the cover a bit. I would suggest you do a test print of just the edge first. You can scale it up or down slightly if needed.

Update

Added version of Base with a larger desiccant tray. Also Added covers with Creality and Ender logos.

Also, included step file for plain cover so you can add your own logo or design if desired.

Update

Added cover with Creality CR-10S Pro logo.