C.R.I. 3" & 4" Silver Line Series submersible pumps are built with thermoplastic impellers, diffusers and inbuilt check valve. All vital components of these pumps are made of corrosive resistance thermoplastic and the shaft is of SS 304/431. Pumps are multi stage centrifugal type. The optimal design of impellers and diffusers enables the best possible hydraulic efficiency. The pump is firmly coupled to a submersible electric motor which operates submerged beneath the surface of water. Built in check valve prevents back flow and reduces the risk of water hammering. All mounting dimensions are in accordance with NEMA Standard motors.