The cubes to which you refer were manufactured in Korea.
I purchased three or four in Toronto at a Korean trade show about six years
and still have them in perfect working order.
Sorry I can't give you anymore information than that,
other than to say that they are trully amazing in that they
have lasted extremely well and require absolutely no maintenance.
The red's a little hard to distinguish from the orange
in the wrong light but that is the only problem.
While we are on the subject, does anyone know where to acquire
a 5x5x5? There was a source in London two years ago but they ran out
and haven't been seen since.
Also I'd like to acquire the globe
on which the equator, greenwich and 90' meridians rotate.