A porous film is characterized by the presence of tiny holes (pores). This is the type of film produced by laser perforation. Non-porous films are breathable without the presence of pores. Therefore their structure and production is a lot more complex than in the case of conventional films.However, in some cases the use of non-pourous films may be required. Non-pourous films offer a controlled barrier to the environment and prevent the intrusion of liquids, dirt and small insects.