The “SIA 4” series submersible pumps are made of AISI-304 corrosion-resistant stainless steel on all the main pump components, and the optimum design of the impellers and diffusers allows better hydraulic efficiency. The built-in check valve prevents backflow and reduces the risk of water hammer. High durability, good abrasion resistance. Easy assembly and high axial thrust resistance. Extremely durable, water lubricated bearings. All installation dimensions of the pump comply with NEMA standards.