The most counterfeited high-value AQ cables have been the Sky and K2. For those particular models, you’d want to buy from a trustworthy seller that can verify the cable’s history all the way back back to purchase from an authorized dealer. From user reports, the problem is that these models’ counterfeits will have the EXACT braid and sheath used by the real deal (i.e. this is the part of the cable that’s made in China), while the interior metal is of vastly inferior quality (copper of unknown origin, or worse).
I’ve bought several very expensive used silver AQ cables over the years. And I’ve ended up with all of them having retermination/upgrade work done at AQ headquarters, so they can all now be guaranteed as 100% authentic. With careful buying, I’ve not yet encountered a counterfeit. Proceed with caution, work only with reputable sellers, and do your research - and you’ll almost certainly be fine. I’m fine with the way AQ handles counterfeits, especially given that they perform work on any genuine used cable for a reasonable fee - even if out of warranty, and whether you’re the original owner or not. I fully trust their judgement on whether a cable is genuine or counterfeit. If one day they send me a response saying they’ve destroyed one of my cables as counterfeit, I’d be bummed, but wouldn’t question them.
I’ve bought several very expensive used silver AQ cables over the years. And I’ve ended up with all of them having retermination/upgrade work done at AQ headquarters, so they can all now be guaranteed as 100% authentic. With careful buying, I’ve not yet encountered a counterfeit. Proceed with caution, work only with reputable sellers, and do your research - and you’ll almost certainly be fine. I’m fine with the way AQ handles counterfeits, especially given that they perform work on any genuine used cable for a reasonable fee - even if out of warranty, and whether you’re the original owner or not. I fully trust their judgement on whether a cable is genuine or counterfeit. If one day they send me a response saying they’ve destroyed one of my cables as counterfeit, I’d be bummed, but wouldn’t question them.