They are considered pure beryllium foil diaphragms. However, there is always the fine-print. \n\nThat the foils are attached via plastic to adhere to the driver. I imagine that is quite significant in the movement. \n\nQuestion, how significant is that plastic connecti g point to the diaphragm? Does that negate the claim that this is pure beryllium? \n\nIs this setup only a small step forward, from plastic that was coated with Beryllium? Or a bug step forward? \n\nI am not trying to throw any negative shade. Just curious, and others would know better.