Window film is optical grade polyester sheeting with embedded colored dye and/or metal particles that helps reduce the transmission of solar heat, light, and ultraviolet rays through glass. A Warranty Backed by One of the World’s Most Respected Companies. What good is a lifetime warranty from a company that wasn’t around 10 years ago and probably won’t be here 10 years from now? Selecting Window Films gives you peace of mind. That’s because we offer some of the most comprehensive warranties you can get. Window Films are backed by a limited-lifetime warranty should your window film need replacing. Give us a call today!