Japan KISHO plating crystal hardness is about 6H, we will ask why it is not 9H plating crystal, the higher the hardness, the better the product effect? As a manufacturer of plated crystals, it is natural to develop such a 9H plated crystal, but after testing, it is found that the higher the hardness, the more likely to crack, so most of the hardness 9H is a means of publicity. http://www.kisho-coating.com