FLAT DUCT CONNECTOR / COUPLER: A connecting element that can be placed between the start and end points of an air technology system, for connecting flat ducts to each other. The system can be more easily covered/hidden by using the ventilation ducts with a rectangular cross-section and the corresponding fittings. It has a smaller "thickness" size compared to the elements of the equivalent "traditional" circular cross-section pipe system, so it can also be placed in narrower places (e.g. above false ceilings, behind floor beams) without reducing (narrowing) the useful cross-section. The constrictions used in the ventilation system can result in greater pressure loss and higher noise from air flow. If the device to be installed has a connection with a circular cross-section, the so-called to one of the "transformer" adapters, which of course can also be found among the air technology accessories, within all size categories. Characteristics of Gonal Fit&Go system elements: An air-technical element with a special rubber seal on the connection surfaces, which can be used to create a system classified in the highest air-tightness class ("D" air-tightness class!). The advantages of this:- Fast and precise fitting;- Can be installed without tools;- Fixed, displacement-proof rubber seal at the factory;- The position of the fittings can be changed / fine-tuned afterwards without deteriorating the sealing efficiency; - It does not require the use of other solutions that improve/increase the airtightness;- A leak-free system can be created by using them;- Lower noise level resulting from air flow;- High energy efficiency.