This is a remix of the awesome silica box by @compute4you. I liked how the silica beads were in the same compartment as the filament when the spool is placed in a vacuum sealed bag instead of in the core. I attached a hygrometer mount so it can be in the same area and also so that I wouldnt forget to put it in the bag before sealing it, plus it is easily visible. I also made the sides of the box a little thicker to 0.5mm instead of 0.4 to make them feel a little stronger.
It fits perfectly in the Bambu Lab spools and in the Atomic Filament spools. These are the only two spool types that I have to test it on but I'm sure it will fit on many other brand spools.