There really isn’t much to add about the solution that I’ve been using that hasn’t been shared on this rather long thread posted here.
If you’re curious as to what was in the photo, it merely came from this Printables profile but there are many others that are similarly designed.
https://www.printables.com/model/742565-wildone-drill-less-drybox-cap-with-hygrometer-and-/files
I used that one because it included STEP files, which makes it easy to modify. I modified the model to fit a PTFE fitting and added a stub with a 1.75mm hole as a filament anchor during storage.
I generally have avoided cereal box designs due to poor value and space inefficiency. They only fit narrow spools, Bambu spools as an example, are too large. Despite buying two sets on sale for under $4 each, I would have regretted paying full price. They clutter my shelf, and after adding parts for a “live feeder” brings the total cost to over $8 per box—bringing the total cost near the cost of 8 spools of PLA at the prices I pay. A purpose-built dryer was a more sensible solution to me at under $60.
While some swear by these dry boxes, they don’t make sense to me if one has a single printer setup. A member recommended a better bulk spool storage solution in the link above which drove cost down to under $3/spool, which I purchased at a local Home Depot. I’m careful with over-spending on every cool gadget I see since this hobby spending can quickly get out of control and I’ve found that many of the things I printed/designed/downloaded, didn’t get nearly the use I thought they would.