A small rounded box for storage and transport of up to four Micro SD cards.
Has a thread to securely hold the box closed.
The unique thing are tiny springs for each receptacle to keep the cards in place even when turned upside down.
Designed with openSCAD (included) to allow free changing of everything.
The fantastic thread library (see remix source files) usually makes almost perfectly well running threads, but some PTFE spray makes it really smooth.