The Dux Ducis Tempered Glass for Samsung Galaxy A42 5G is made of Japanese safety glass, type Asahi Glass. The film adheres perfectly to the surface of the screen and does not form air bubbles after application. The film is fixed, without touching its adhesive surface (the part that sticks to the screen), respecting all the cutouts corresponding to the type of phone. Then gently press, with the help of the napkin, on the entire surface of the foil to make it stick perfectly. Clean and degrease the surface of the screen beforehand with alcohol, then wipe it well with the napkin included in the package to remove any residual traces left from the first operation. The Dux Ducis Tempered Glass for Samsung Galaxy A42 5G is designed to withstand even sharp objects: knives, cutters and keys. In case of a strong shock, the film will break into small pieces, which remain stuck together, protecting your phone's screen. Degree of protection: 9H (same resistance as in the case of car windshields). Careful! The foil is NOT compatible with the fingerprint sensor integrated in the display.