Goulds WE0311M Xylem Residential Wastewater Submersible Effluent Pump, 115 volt, 1/3 hp Impeller: Cast iron, semi-open, non-clog with pump-out vanes for mechanical seal protection Balanced for smooth operation Casing: Cast iron volute type for maximum efficiency Mechanical seal: Silicon carbide vs. silicon carbide sealing faces Shaft: Corrosion-resistant, stainless Steel, threaded design