Exclusively designed perforated diffusers are mounted on suspended ceilings or plaster walls. There can also be an open and modern installation indoors without covering the diffuser. These diffusers are specially designed for those spaces where a large amount of air is required evenly, smoothly and without drafts. This type of premises are usually offices, workplaces, kindergartens, schools, as well as, industrial and research laboratories. A separate cleaning hatch is not required.