Amazing product - I have been using it for at least 10 years since it first came out, I got it through skroutz but directly from abroad, I think France.
The only reading glasses that you can put in the front pocket of your pants and they won't break, so you can have them with you at all times.
They are not made of bone as the description says, but from plastic. At some point, they wear out or break, after about a decade... Conclusion: I ALWAYS have them with me in my pocket... regardless of whether I use some other glasses too...