Beryllium is the only metal capable of scratching glass due to its high rigidity, and is the material of choice for tweeter diaphragms. Two years of research and development at Focal have resulted in the shaping of an inverted dome in pure Beryllium capable of covering more than five octaves. An exclusive technology that we have combined with another major innovation: the "M" profile, which brings two decisive advantages: an even lower directivity of sound, for an ever more flexible listening position, and a significant gain in dome rigidity, which further reduces distortion and thus delivers quality sound. It is combined with a larger coil (25 mm) for unrivalled power handling.