This is a desiccant box designed to hold silica gel and fit inside a spool.

You can place multiple silica gel bags inside, or cut-open them and pour the silica beads directly into the box.

Since silica bead sizes can vary, smaller beads may fall through the holes. To prevent this, I recommend using these organza bags: https://s.click.aliexpress.com/e/_c35s6NWh

Alternatively, you can use larger silica gel beads, such as these color-changing silica that indicate when they are saturated: https://s.click.aliexpress.com/e/_c3BLgJi1