DISA QF Duct System The DISA duct system is manufactured from fully galvanised sheets and is characterised by great stability of form and a smooth surface. The components have a rolled collar, over which the QF clip is fitted. The clip has an inner gasket to ensure that an air tight seal is achieved. It requires no tools to assemble or modify. The QF system has a complete accessory range with Y-pieces, branches, cut in branch, adapters, reducers, sliding dampers, automatic dampers etc. It ensures individual fitting and great flexibility - including adaptation to other duct systems.