I had a client who wound up with one of those not realizing what it was, which caused him no end of problems until I ultimately figured it out confiscated it from him. He got a regular US inch one in exchange. I had to look it up at the time, too, because the notion of there being a Chinese knockoff inch that's subtly inaccurate is one of those things that just seems so ridiculous on its face that it simply can't be true, right? Except it totally is.