They are clear, flexible, transparent or translucent material produced from PET polymer, a linear, thermoplastic polyester resin. PET film is a high-performance polymeric film and is generally more expensive than other polymeric films with several unique properties that are required for various end-uses. PET film has certain inherent desirable qualities such as high tensile strength, durability, heat resistance, good gas-barrier properties, dimensional stability, chemical inertness and clarity. PET film is available commercially in a range of widths, thicknesses and properties depending upon the needs of end users. It can be made as a single layer or can be coextruded with other co-polymers into a multilayer film encompassing the desired characteristics of each material. The distinct physical properties of the various types of PET film can be imparted into the product either during the polymerization of the PET resin, by the addition of chemicals such as slip modifiers (surface modifiers) or color additives, or subsequently during the PET film production process where various surface finishes may also be imparted by externally treating the films' surface(s).The biaxial orientation of the PET film makes it suitable for such applications as food packaging, electrical insulation, and printing sheets by increasing the product's crystallinity and thereby improving its tensile strength, heat resistance, and gas-barrier properties.