66-30-2-2 Cu-Ni (C71640, CW353H) Tube is a modified version of 70-30 alloy tube and contains 2% iron and 2% Mn and can withstand higher flow rates than 90-10 and 70-30. The other important note is that it has slightly less resistance to localized corrosion. These C71640 products are mainly used as condenser tubing. Commercially, UNS C71640 condenser tubes are mainly in demand by Industrial Plants. It was originally developed for higher resistance to erosion corrosion in the presence of suspended solids and has been extremely successful in multi-stage flash desalination plants, particularly in the heat rejection and brine heater sections.