The full face tempered glass is a full-coverage tempered glass screen protector, specially designed to protect your mobile phone's screen from scratches and other damages. In the event of a fall, it does not guarantee that the screen won't break along with it, but it provides additional protection.
It does not affect the functionality of the screen. It has adhesive across its 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 adhesive around the edges wears out.