Hello, I find out this info on Ebay and its not 100% accurate: (please read my reply) 1. Always check the serial number on the glasses Cartier has a seven digit serial number that usually starts with a three(well from the authentic pairs I've seen it has always started with a three) 2. Once you see the serial number call Cartier at 5 and read of the serial number and make sure the glasses are as described.