This is a simple solution to keep a single spool dried in an airtight box.

You need to print:

• two pivot supports
• two clips (or use two M8 nuts)
• two filament "rings" (choose the right size, or ask me for a different size)

You need to buy:

• the box (I used this one https://www.amazon.it/dp/B086QDFWX3/, but you can use any similar box)
• one M8 threaded rod (choose the right length that fit the box)
• two 608Z bearing
• four M3x8mm screws
• four M3 insert nuts (with outer diameter 4mm and length 3mm) or regular M3 nuts
• PTFE tube that fit your filament size
• one cable gland (that fit the PTFE tube)

Optional: if you want to put a hygrometer inside the box you can buy a circular one (like this https://www.amazon.it/gp/product/B07JG9QZ2B/) and print a connection ring (the one I provide fit the linked box and hygrometrer).

Thanks to

• rowokii for clips https://www.thingiverse.com/thing:767317
• RichRap for dry-box idea https://www.thingiverse.com/thing:2778707