Window film is a thin laminate film coating that can be installed on the interior of glass surfaces in automobiles, boats and buildings. Many different types of films are available from a variety of manufacturers, with polyester being among the most common. It provides transparency, tensile strength, retains its shape with minimal shrinkage over time, and is able to accept a variety of surface-applied or embedded substances such as pigments, dyes, ultraviolet inhibitors, and more.