The Residual Resistivity Ratio (RRR) is a propertie of pure aluminum products which is used for the production of some superconductors wires (especially phsyics of particles at the CERN for example).
According to the purity, RRR range covers 700 to 8000 values.
PHP is used to deliver either small quanities or big (several 100 tons) with various shapes (billets, bars, plates)