This is really a protective glass, not a film! If you stick strictly to the manual, it's really easy to attach the film accurately. The air goes out by itself, if the film attracts. When Xperia Z3 it is very important to know that the film is cut on the top left, right in front of the camera but not! This is by design, the cut-out opening on the top left is for the proximity sensor! For lay people, like me, the sensor, the phone needs to make it noted that holding the phone to your ear and then interpreted as a "call". Otherwise would with a touch screen phone yes constantly triggered some function when you hold it to your ear. This sensor must probably remain free, therefore the cutout in the protective glass. The front camera requires the recess does not seem to make perfect photos. I write therefore in such detail because I was very irritated by the opening on the seemingly "wrong" side during the initial installation of the protective glass and wanted to raise the protective screen in reverse. Since the silicon adhesive layer is only on one side, you can not afford the other way around the disc. So do not make the same mistake I did, first of all read the manual! I now plan each matching protective glass panels on the Xperia Z1, Z3 and two on a Z Ultra and only regret that I have learned this protective glasses know until now. As it unfortunately does not hold Sony necessary, or the like to provide its expensive top devices with Gorilla Glass, you need an additional protection absolutely. My Z Ultra is already a year has passed and has unfortunately taken some marks on the display of it before I have now applied the protective glass. The responsiveness of the display to finger movement is not affected, I even sometimes feel the display responds even better, but that may be my imagination. Against keys in your pocket, the display is certainly immune. Without protective glass, I got myself quickly clear scratches. So I can only recommend this hard glass shield. She is also so thin that they do not really notice uncomfortable and carries with 0.3mm thickness hardly noticeable. Why the manufacturer did not applied (in my case Sony) such a protective layer from the factory?