These subcollectors are designed to respectively connect a vertical spiralled duct (dia 125 mm or dia 150 mm) to a horizontal rectangular duct. They are equipped with an air conductor to keep the resistance as low as possible and are glued together on the inside in order to prevent any leakages. A connection piece MDF is necessary to connect them with a rectangular duct KTL-SD.
Subcollector made out of KTL coated steel (5µm): thanks to this KTL coating, the subcollector is resistant to the corrosive elements of the cement screed (compression strength 80 kg/cm²)