You can stick a static film onto the windscreen before attaching the mount. This makes it easier to remove the dashcam from the windscreen with the mount and reattach it. This can be useful if you want to use the dashcam in multiple cars. If you only use the dashcam in one car, you might as well stick the holder directly onto the windscreen, which also looks a bit nicer. The use of such a static film is therefore optional.