The full face tempered glass by Dux Ducis is a full coverage tempered glass, specially designed to protect your phone screen from scratches and other damages. In case of a phone drop, it does not guarantee that the screen will not break along with it, but it is an additional protection. It does not affect the screen's functionality. It is 9D, which means it has undergone special processing to acquire curved edges that cover the entire surface of the phone screen. This way, it is not noticeable that the screen has protection, but the curved edges are also protected. It is compatible with the Redmi Note 9.