To protect my PLA filament coil against moisture, I use reusable silica beads (aliexpress) but I had to find a solution to condition them effectively by taking the least possible space. hence the idea of making a box more suitable to be placed in the axis of a coil.
Tip: a good way to use a vacuum packaging (at will) is to use bags originally designed to store linens, we can store two reels of 1Kg with 40x50 format bags, the result is rather satisfactory.
Vacuum Storage Bag
Information: When the silica gel is saturated with moisture (it changes color) place it in an oven at 60 ° C for 3 hours, after it can be reused again.