These extra wide webs are ubiquitous whenever it is necessary to cover a large surface. From three layers construction films where the demand is toward mechanical properties, to large greenhouse films, where a combination of factors is simultaneously required. This is a very good reason to opt for sophisticated coextrusion in order to enhance the standard three layer with Heat-effect and UV-resistance features with further performances such as antifog, peculiar light diffusion and multi-seasonal resistance in order to withstand to the external wheather conditions as well as the resistance to cultivation chemicals. As all these added features are obtained by special addition of specialty masterbatches, the use of specific ingredients in discrete layers is becoming the driver to rise the technology bar of these large production systems. Three layer conventional lines are now paralleled by five layers system, with growing interest to 7 layer specialties.