Filament Desiccant Holder for Spool

I have a filament drier, and the vacuum storage containers are brilliant, but expensive.   A Freezer grade zip lock bag works well, but still lets a little air infiltration as the seal isn't perfect and the bags can have micro defects.  This cup fits in the spool hole and if you use indicator desiccant and print it in clear, you can see the moisture state.  I printed it in Taulman Clear PETG.

The lid snap fits in, and you might need to bend the lid or squeeze the cup to get the last ‘nub’ in.  The desiccant I have from McMaster pretty much stays in, but you don't want to store the spools vertically. The cup sits flush so you can stack the spools.

Clear PETG

0.2 Layers

Low (5%) or even no infill for better vision inside.