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