Zoeller 137-0078 Model 137 Sump Pump 0.5 HP 230V 1PH 15' Cord AutomaticZoeller Model 137 Sump Pump Description Our Model D137 Sump Pump is an all cast iron pump designed to remove unwanted groundwater in basement sump applications. The professional grade, 1 2 HP D137 is great option when a high flow cast iron sump pump is required. Known as the Flow Mate, the D137 is a fully automatic float operated sump pump. The white polypropylene float is solid so it cannot become waterlogged. This ensures that it is always buoyant