Had a 6 small dices laying freely around so I made a small box to store them.
The 2 halves of case are identical, each have 2 magnets. I used 5x2,5mm magnets and the holes are just tight enough to press them in with plier, no glue necessary.
Size of dice - 10mm
Printed in PLA, 0,2mm layer height and 15% infill.