Die-cast aluminum flange.N°4 holes equidistant ø8.5 on ø160 mm pitch.Outer diameter 180mm, thickness 6 mm.The double membrane system includes a first element in EPDM rubber, which ensures sealing and also acts as a gasket for the fixing holes, and a membrane in AISI 316 / EN 1.4401 stainless steel superimposed, the only one to come into contact with the product, also guaranteeing greater mechanical resistance.