“9H” on a screen protector isn’t the Mohs mineral scale; It’s a pencil hardness rating from coatings tests. The real protection comes from tempered/chemically-strengthened glass acting as a sacrificial layer plus a case with a raised lip. Here’s how to pick a protector that feels like bare glass, plays nicely with your case, and actually prevents the day-to-day damage your iPhone 17 sees. (Itech Standards, Corning, Wikipedia)