C.R.I. 4 « , 6 », 8 « & 10 » Stainless steel series submersible pumps are made of stainless steel. All major components are made of high quality 304/316 stainless steel and the shaft is SS 304 / 329/431. The best impeller and diffuser design ensure the best possible hydraulic efficiency. These pumps are of the mulistage centrifugal type, which can be firmly connected to a submersible electric motor operating submerged below the water surface. The built-in check valve prevents backflow and reduces the risk of water hammer. All installation dimensions of the pumps comply with NEMA standards.