The full face tempered glass is a full-coverage tempered glass designed specifically to protect your mobile phone's screen from scratches and other damage. In the event of a drop, there is no guarantee that the screen will not break, but it provides extra protection. It does not affect the functionality of the screen.
The black frame covers the entire screen surface, including the edges. It features adhesive across the entire surface, unlike edge glue screen protectors which only have adhesive around the perimeter. This helps with better application and smooth operation of the touch screen.
Additionally, it prevents dust from passing underneath, which can happen with edge glue protectors when the adhesive around the perimeter wears out. It can be removed at any time without leaving marks or causing issues to the screen.