Serfilco "HE" chemical pump is capable of "total" chemical resistance, both internally and externally with its non-metallic construction of all wetted components, choice of seal assembly and elastomer materials. Enclosed centrifugal impeller. Engineering type plastics provide application to a variety of chemicals which would be corrosive to other materials of construction. The totally enclosed impeller allows this pump to operate at peak horsepower efficiency across a broad range of operational flow/head requirements. Double mechanical seal model requires water lubrication of seal faces & allows the pump to be used for chemical solutions containing abrasives, high salt concentrations & electroless plating solutions. See the Dri-Stop switch 99-1152R under accessories.