C10200 - also known as Oxygen-Free (OF). While OF is considered oxygen-free, its conductivity rating is no better than the more common ETP grade below. It has a 0.001% oxygen content, 99.95% purity and minimum 100% IACS conductivity. For the purposes of purity percentage, silver (Ag) content is counted as copper (Cu).

C11000 - also known as Electrolytic-Tough-Pitch (ETP). This is the most common copper. It is universal for electrical applications. ETP has a minimum conductivity rating of 100% IACS and is required to be 99.9% pure. It has 0.02% to 0.04% oxygen content (typical). Most ETP sold today will meet or exceed the 101% IACS specification. As with OF copper, silver (Ag) content is counted as copper (Cu) for purity purposes.

Many cables today are advertised as using "oxygen-free copper," copper which has been annealed in an oxygen-free atmosphere. OFC is popular in audio cables, and has begun to make inroads into the video cable market as well.[5]. The merits of OFHC for such applications are, however, minimal.

Many owners of high-end audio and video equipment value oxygen-free copper. Behind this demand is the belief that oxygen-free copper will have enhanced conductivity or other electrical properties that are significantly advantageous to low frequency (audio) signal transmission. However, conductivity specifications for C11000 ETP and C10200 OF coppers are identical. In practice, nominal conductivity differences between the three grades listed above are less than .1% of .1% at room temperature.