Cast iron pump volute for long life and quiet operation. Designed for small sump pits. Mechanical float switch provides positive on-off action for many years of safe, reliable service. Overload protection keeps motor from overheating. Unitized seal for long life. Top suction strainer stops foreign particles before clogging the pump. Thermoplastic top assembly will not rust or corrode. Minimum sump diameter 11"; on level, at 9" off-level at 4". U.L. Listed.1-1/2" NPT discharge and reinforced thermoplastic base.