This 47 mm diameter container fits inside some of my filament spools. It holds a fair amount of dessicant and protects a vacuum bag from popping in the middle when applying vacuum.

I made 50mm and 60mm versions, what size would you like to have added?

It has a triple started thread for easy operation and making sure the lid doesn't open by itself.

Dessicant is widely available on amazon or ebay, I would choose a color changing version so you know when to regenerate is.

I might make a lid holding a hygrometer, would you be interested in that?

regards,

Pea