The genius of this puzzle is its simplicity. Thank you for making this!
You can print the chain in place which I think is a little more graceful way to do it. Anything that avoids the use of superglue has to be an improvement. This chain will not break.
You'll of course need to use a brim to print the chain, but it is easily removed after printing. Supports are not necessary. Print .20mm with 15% infill.
I slightly beefed up the end of the lid. It broke it for me immediately when trying to force it on; this fixes that.
Lastly, the box was almost too short for the chain to fit, so I vertically extended it exactly 1mm.
The author remixed this model.
The original required superglue to link the whole chain together. This allows you to print the chain in place with no assembly required. Also the lid was a little weak on one side so I added a mm of thickness to beef it up.