The tempered glass by Partner Tele is a hardened glass, specially designed to cover and protect your phone's screen from scratches and other damage. It does not affect the screen's functionality. In case of a phone drop, it does not guarantee that the screen will not break along with it, however, it is an additional protection. It is 5D, which means it has undergone special processing to acquire curved edges that will cover the entire surface of the phone screen. This way it is not apparent that the screen has protection, but additionally, the curved edges are also protected. It is compatible with Samsung Galaxy A21.