Heat-shrink PET films are growing rapidly - by some accounts more than 10% per year - as food processors opt for packages with more elaborate graphics. PET films are also finding their way into heat-seal lids that bond strongly to various substrates but can be easily peeled. The films are used for dairy and snack foods, for fruit cups, and for pharmaceutical products. Oxygen and moisture-resistant barrier packaging made from metallized PET films compete with foils and with metallized oriented polypropylene (OPP) films. Metallization of the films, whether PET or OPP, helps shut out ultraviolet (UV) light that can hasten food spoilage. Polyester films can be coextruded with other layers to create labels for packaged products with high-quality graphics and UV blocking properties.