M137 Zoeller Automatic Cast Iron Sump Pump 1/2 HP Effluent or dewatering submersible pump for septic tank, low pressure pipe (LPP) and enhanced flow STEP systems. Castings - Model 137, all cast iron ASTM class 25, 2500# tensile strength.Corrosion resistant powder coated epoxy finishDurable cast iron construction - switch case motor and pump housing, base and impellerFloat operated 2 pole mechanical switch (automatic units only)No sheet metal parts to rust or corrodeOil filled and hermetically sealed, automatic reset thermal overload protected (1 Ph) motorUpper and lower sleeve bearings running in bath of oilCarbon and ceramic shaft sealStainless steel screws, bolts, guard, handle, arm and seal assemblyMaximum temperature for effluent or dewatering 130°F (54°C) (extra duty 140°F 60°C)Passes 5/8" spherical solidsNo screens to clog1-1/2" NPT discharge (1-1/2" x 2" PVC Adapter fitting included with BN & BE Models)On point: 10"Off point: 2 3/4"Simplex and duplex systems packaged systems availableVariable level control systems available designed for heavy duty effluent applications