To be honest, I don't recall. That was about 10 years ago when they were released. I think I recall ceramic hardness and ceramic weight, by volume. Much like the Gold Cermets of old, I didn't find them to be a outright better choice, and they were significantly more expensive.
Just to be clear, I think the Torzites are an outstanding guide and we're really splitting hairs here, other than price. Also with the Gold Cermets. You aren't going to go wrong with Torzites and I've put many sets of them on rods without any issues or complaints.