Crystalline automotive window film from 3M uses multilayer nanotechnology with hundreds of precise layers that are less than the thickness of a Post-it Note. With this technology, 3M Crystalline automotive window film is capable of rejecting more than 66% of incident solar radiation with high visible light transmission. The film offers the benefits of darker window films, with the option of being virtually clear in color. The metal-free construction of the window film helps reduce the typical problems with dropped cell phone calls and weak signals commonly caused by traditional metallic window films. The film also blocks up to 99.9% of UV light, delivering a total Sun Protection Factor of more than 1000.