... D373H-C.P Wafer Multi-layer Metal-to-metal Butterfly ValveAdoption Standard1)Nominal Diameter: DN50-DN6002)Design standard: GB/T ... , stainless steel, Cr .Mo .SteelSeal ring: Stainless steel, multi-layer asbestos with temperature resistantStem: Stainless steel, Cr .Mo . ... dimensional principle, the compatible to soft sealing and metal multi-layer structure, with best machining and advanced technology. ...