Electrical Conductivity
The ability to conduct electricity, as a percent of the International Annealed Copper Standard (% IACS), which is equal to 58 x 106 S/m. Reported for conductive materials; for insulating materials, electrical resistivity is reported instead.
100% IACS is not a physical limit, and can be exceeded. Conductivity values, especially those expressed in % IACS, refer to volumetric, and not surface, resistivity.