The two new Zenith El Primero 36,000 vph (36,000 vibrations per hour being the beat rate of the caliber), are both the middle 42mm size. Yet, the most modern feature is clearly the case material, a black ceramicised aluminum. Basically you can understand it as a fine ceramic coating over an aluminum base. Previously we’d only seen this in the El Primero Range-Rover Limited Edition, but now its going main line.
And, because you know my curiosity, I grilled the product development team on the advantages and drawbacks of such a case. Lightness is a pretty obvious characteristic, but another one I learned about was related to shocks and scratches, clearly something you never look forward to but which inevitably happens. So the vickers hardness of this material is lower than ceramic but it does not shatter on impact. Scratches can arise, but they are more likely to be deposits from the material that the case scratched against than a disappearance of the coating, so they can be buffed out at service, through sandblasting that will give a brand new finishing to the case.