Description Submersible well pumps 4 inch"little giant" 2 - wire 230 volt - 12 gpm h.p. =1/2 4 inches submersible deep well pump. Powered by a 2-wire, industry standard VMC motor. Built-in check valve prevents backflow and ensures system pressure. Built-in suction screen and 1- 1/4 inches NPT thermoplastic discharge head helps to prevent debris from clogging impellers and provides full flow performance without the risk of corrosion.