Best structure design, has a dry motor, IP68, double mechanical seals, equipped with an auto-cut protection, pump casting, outer cover is stainless steel, and acid-resistant silicon carbide seals. The stainless series is suitable for all light acid, corrosive and/or sea water application fluid in pH values between 4 to 10pH. For strong acidity and alkalinity applications, please use the specified chemical pump. Investment Casting Precision casting with the use of an advanced stainless investment casting method that produces the highest quality with a smooth surface finish. Viton O-ring Viton O-rings are used throughout the pump to give better pump life in corrosive acid and aggressive media. Austenitic Stainless Steel – SUS300 series – is used in SF/SA series. SUS316/SCS14 is better than SUS304/SCS13 in water application of light acid-base.