My doubts centre over the label,
If that is for the French market "Maitre Verre" has no meaning here... Maitre verrier, meaning master glass maker, might, but being honest, even that label could be so mis-leading, few serious buyers in France would bother.
The web-site is less than informative, so could this stuff be made in China, and re-labelled?
I do not need it signed, merely better info, which, on the site suggested, is non-existent

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regards,
Marcus