"ZAC" stands for Zero Attenuation Concept. The innovative curving of the fiber core tip to achieve zero divergence loss allows the use of a plastic fiber core, achieving the same transmission quality as that of glass fiber - while affording the strength and flexibility of plastic. In other words, as with all the Supra products, you"ll have top-drawer performance; thanks to superior, innovative engineering, less expensive and more practical materials achieve results commensurate with those of much more expensive cables. And like all the products we sell, you can try ZAC TOSLINK for 30 days; if it"s not everything we say it is, return it to us (in mint condition) for a full refund.