Kinda disappointed. I had high hopes and ordered 2 of theses. I know the diameter is supposed to be slightly larger, but it's too large the shine does not lock in at all, additionally I have the original pebble band and with out the shine in place , the adapter is tight to slide on to the band, when attempting to snap the shine in, it is impossible because it is too tight with the band in the way. I'm not sure if the shine dimensions changed or not, but this is simply not functionable.
I don't know much about 3d printing, but I would think if it were made of a hard rubber , and slightly deeper , it might hold better.