Updated August 2026 Look at almost any tempered glass screen protector listing and you will find "9H hardness" printed somewhere, often next to a diamond icon. The implication is obvious: 9 sounds close to 10, diamonds are a 10, so this glass must be nearly diamond-hard and nearly scratch-proof. Almost none of that is true, and the way 9H gets used is one of the most persistent bits of misleading marketing in phone accessories. The spec is real, but it comes from a much humbler scale than most buyers assume. Here is what 9H actually measures, why it is not...

Updated August 2026 Every screen protector listing says "tempered glass" somewhere, usually in bold. Most shoppers read it as a generic quality word, like "premium" or "HD." It is not. Tempering is a specific manufacturing process that changes the physical structure of glass, and it is the reason a good glass protector can take a hit that would crack your phone's display. Here is what tempering actually is, how it works on the thin glass used for protectors, and why glass beats plastic film for most people. Ordinary glass breaks easily. Here is why. Glass is strong in theory. In...