The full face tempered glass of Idol 1991 is a hardened glass that covers the entire screen, specially made to protect the screen of your mobile phone from scratches and other damages. In case of a drop, it does not guarantee that the screen will not break along with it, however, it provides an additional protection. It does not affect the functionality of the screen. It has adhesive on its entire surface, unlike edge glue protectors that only have adhesive on their perimeter. This helps in better application and smooth operation of the touch screen. It also prevents dust from passing underneath, which can happen with edge glue when the perimeter adhesive wears off. It is 9D, which means it has undergone special processing to acquire curved edges that cover the entire surface of the mobile phone screen. This way, it is not apparent that the screen has protection, but the curved edges are also protected. It is compatible with Mi 9.