Complete drybox solution using IKEA 365+ food storage container 10.6l/358oz.

The parts are designed for standard spools with 55/54mm hub diameter. The quick release fittings for the teflon tubes are the "smaller" (6mm) type. The hygrometer is mounted on the inside, there is no opening cut for the display.

Hint: It works best to screw on the quick release fittings while the part is still hot and soft. Otherwise it might be necessary to cut an M6 thread.
I bought the silica gel cheaply in the automotive section of a hardware store. It is sold in 1kg bags and used to dry cars interiors.

Spool size:
The spools shown in the picture have about 65mm width and 200mm diameter. The hub is 54mm diameter on one side and 55mm on the other. I believe this is the most common spool size I have seen. If your spool is significantly larger than that, it will likely not fit in the container.

Hardware needed:
18x M3x8 (or longer) bolts
18x M3 nut
1x M8 threaded rod for spools (length 172mm when fixed midway of box height)
2x M8 nuts and some washers as spacers between spools
2x Pneumatic air quick release fitting with 6mm diameter thread (see picture)
2x Teflon tubes
1x Cheap amazon hygrometer (see picture)
Optional: Another quick release fitting and M4 bolt + t-slot nut for frame mount (see picture)

Print:
2x outlet inside
2x outlet outside (straight or 30degree angled)
2x roller mount inside
2x roller mount outside
2x roller hub 54mm (smaller side of spool)
2x roller hub 55mm (larger side of spool)
1x hygrometer mount inside, outside, spacer
1x (optional) 2020 frame mount

Ikea US IKEA 365+ Food container with lid 358oz
Ikea Austria IKEA 365+ Vorratsbehälter mit Deckel 10.6 l
Ikea Germany IKEA 365+ Vorratsbehälter mit Deckel, rechteckig/Kunststoff10.6 l
Ikea Australia IKEA 365+ Food container with lid, rectangular/plastic10.6 l
Ikea Russia ИКЕА/365+ Контейнер для продуктов с крышкой, прямоугольн формы/пластик10.6 л
Ikea Sweden IKEA 365+ Matlåda med lock, rektangulär/plast10.6 l
Ikea UK IKEA 365+ Food container with lid, rectangular/plastic10.6 l