A:Answer I’m not able to check at the moment but will follow up with a definitive answer. However, having purchased a plethora of high-end Audioquest cables (Thunderbird, Vodka, and Carbon HDMI cables and 2 Diamond optical cables) I would say glass. i will confirm and follow up. I can say you will absolutely NOT be disappointed if you purchase the Diamond optical cable. I wouldn’t hesitate to purchase another if needed. Although we’ve been making a move to the eARC equipment and as such haven’t had as much of a need for the optical cables.
