Bronze Z - The latest choice now offered by PHC. In our standard shape, the unique combination of density, hardness, and evenness (thanks to the 'Z' processing) offer what many are finding is that extra step in all directions towards that 'magic' mouthpiece! Superior evenness over a very wide dynamic range and a wonderful feel of projection of sound present on the hand in the bell and off the back wall of the hall. Works particularly well with a Stainless Steel rim! This material favours production of a warmer sound.