A privacy screen protector serves double duty as a screen guard to keep your display scratch-free while also keeping your data safe from prying eyes.  Like a regular screen protector, these can be of the PET film or tempered glass variety. But, it has an additional anti-spy layer that limits the viewing angle of your display. The viewing angle has to be narrow enough so that people standing or sitting next to you are out of range. If the viewing angle is too wide, it defeats the purpose of having a privacy screen protector. On the flip side, if it’s too narrow, it may impact your own viewing experience.