1.Flow curve tendina to straightline.excellent regulation performance 2.Wide selection of materials applicable for various mdei Body:Cast Lron , Ductile Lron,Aluminum Bronzd, Stainless Steel,CF8M Stainless Steel,Carbon SteelDisc:Plated Ductile Iron, Aluminum Bronze ,Stainless Steel , Titanium Steel , CF8M Stainless Steel,Carton SteelStem:Stainless Steel ,Carbon Steel.Bushing:Lubrized Bronze, ...