This is a keychain I made for my favourite dice, it holds chessex and standard generic aliexpress dice snugly.The hinge works by using a small piece of filament, and the halves are symmetric, the holes are tuned for my 3d printer, and are about 2.1 mm wide in Cad, the 1.75 mm filament fits snugly, almost press fit but it can still be disassembled.I recommend using it as a keyring, but as you can see in the photos, even a thick cord will work.I made it so that it can easily be opened up and the dice taken out.