The full face tempered glass is a full-coverage tempered glass, specifically designed to protect the mobile screen from scratches and other damages. In case the mobile phone is dropped, it provides additional protection, although it does not guarantee that the screen will not break.
This particular glass does not affect the screen's functionality. It has adhesive across its entire surface, unlike edge glue protectors that have adhesive only on the perimeter. This helps in better adhesion and trouble-free operation of the touchscreen. Additionally, it prevents dust from passing underneath, which can happen with edge glue protectors when the perimeter adhesive wears off.