Copper C102 is oxygen-free copper (99.95% minimum) with the same high conductivity as standard copper. It is chosen where purity matters, such as vacuum use and brazed or welded assemblies.
C10200 (CW008A) is oxygen-free copper, at least 99.95% copper with oxygen limited to 0.001%. Its electrical and thermal conductivity are essentially the same as standard C110 copper, so the real advantage is purity: It avoids the hydrogen embrittlement risk of oxygen-bearing copper during brazing or welding and contains no elements that evaporate under vacuum.
Copper C102 is suited to vacuum components, conductors, contacts, and brazed electrical parts.