OFC Copper (Oxygen-Free Copper, 101% IACS)

Oxygen-free copper — the workhorse audio conductor. Refined to under 10 ppm oxygen content (compared to ~250 ppm in standard electrolytic copper), which prevents the inter-grain oxide formation that increases resistance and degrades the conductor over decades of service.

Conductivity is approximately 101% IACS — slightly better than the IACS reference standard itself. Used in 80%+ of all audiophile-grade cables, from stock-bundled IEM cables to high-end interconnects, because it delivers most of the audible quality of fancier conductors at a fraction of the cost.

The substrate conductor for most silver-plated and gold-plated hybrid constructions. The standard against which other conductor materials are evaluated.