OCC медь - цельнотянутая из расплава, а не выращенный монокристалл.

с сайта Wireworld:

Цитата:Oxygen-Free Copper (OFC) contains less oxygen than the common ETP (Electrolytic Tough Pitch) copper, making it a better conductor for audio and video cables. OFC is also known as 4-nines (4N) purity because it is specified as 99.99% oxygen-free. OCC is the trademark for Ohno Continuous Casting, the most advanced process for refining and casting copper and silver conductors. OCC copper and silver conductors are guaranteed to be 99.99997% (6N) pure.

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