The VSSC-220x90-DF is manufactured from (white) high impact polystyrene and has a free area of 16,790mm² (Duct Side) to 17,968mm² (Fitting Side). The Self-Seal DF Pipe to Fitting Connector incorporates a gasket to reduce air leakage to an absolute minimum between our PL150 FD ducting and the PL150 Fittings.