I have those! The d12 doesn't charge anymore after a few months, though. Sucks.

EDIT I think people haven't bothered to check what product this is, annoying as this is I think I'll do myself and others a favour by explaining what this is:

These are dice with LEDs in them, a sensor that tells when it hits a hard surface, and transparent digits on them. When you roll them, the sensor picks us a hit and the LEDs make the numbers blink for a few seconds. They come with a case you can connect via USB-C, each shape in the case has a charging pin, touching a small, metal surface on each die, through which they charge. In my case, even though the d12 is in the right position in its shape, it no longer charges. It's still a black die with transparent digits, it just doesn't blink, anymore.