Of course, you’ll also want to make sure your Security Film window is correctly installed. A window that cracks and stays together but falls out of the frame won’t help, so we also seal the glass and security film to the window’s edges.
Unfortunately, Security Film is not completely unbreakable. Bullets can sometimes go right through, though this varies based on the strength. For almost impenetrable windows, you would need to upgrade from a Security Film to a ballistics-stopping, architectural-grade clear poly-carbonate. Still, Security Film has the benefit of staying together under attack, which delays active shooters from getting inside.