PanzerGlass is tempered glass, hardened 9 times more than ordinary glass. In the glass there are several layers:
The bottom layer consists of silicon that makes the glass adhere to the screen, and makes the glass settle perfectly on the phone without bubbles, so there is no reduced sensitivity.
The glass also consists of a PET film which makes the glass more flexible and so it doesn’t splinter upon breaking.
At the top of PanzerGlass there is an oleophobic coating that makes the phone resistant to greasy fingers and easier to clean.