This is yet another desiccant case, it is designed to follow the curve of a standard 200mm spool so it can fit in the edge of a smaller dry box.
The case is sized 6x6x15 cm to exactly fit the box I use and hold 100g of desiccant (photo shows proof ;)).
Print it standing upright, default settings should be fine. I print these in ASA so I can dry the desiccant in the box itself. It uses a simple snap-on lid system that I've found to be really reliable.