12 Mil Clear Security Window Film Security Window Film is designed to slow or prevent entry from a burglar. Protect your family, and your property, with our high quality Security and Safety Window Films. Security Window Film prevents thieves from quickly getting through glass and into your home, and prevents shards from falling should glass be broken. With 99% UV rejection, these security films also reduce fading of fabrics. Our virtually clear security films do not diminish viewing, and are easily applied. 90% Visible Light Transmittance (virtually clear), blocks 99% of UV rays 2 Ply 12 Mil Security Window Film Color: Clear Width: 30 in Length: 25 ft Installation Instructions Additional Information: All security films are meant to be installed on the interior surface of a window. The best method of installation is to remove the glass from the window frame, install the film, and reinstall the glass into the frame. The frame will act as an anchor to the film. If this is not possible, a bead of clear (or white, if preferred) silicone around the edge of the glass, about 24-48 hours after installation, is highly recommended. This will keep the glass and film firmly anchored in the frame if the glass is broken.