Long Service Life Hydro Turbine Runner A polished surface and a sound casting reduce erosion and fatigue, which extends runner life. This runner covers a 150RPM to 1000RPM speed range across common heads. Technical Specifications Service Life Over 25 Years Surface Treatment Polished Speed Range 150RPM-1000RPM Material Stainless Steel ZG0Cr13Ni4Mo Key Features Polished surface lowers erosion and fatigue Speed range from 150RPM to 1000RPM Sound casting for long service life