Well, I'm surprised. I ordered the 49 mm pair before I ordered the 51 mm pair, and they were perfect, just too small. The 49 mm pair were definitely authentic, no problems there. I exchanged them, and when the 51 mm pair arrived, I immediately had my doubts if they were real or not. Everything that was supposed to be there was - each nose pad had a tiny &#34;RB&#34; on them, everything was spelled correctly, and the left lens had a very small engraved &#34;RB&#34; on it. However, the glasses didn't seem quite right. There were a lot of tiny things wrong that made me suspect they were fake. The label on the nose bridge was misaligned, the engraving on the lens was extremely faint (much more so than on the 49 mm pair), there was excess glue around one of the hinges and around a fixture, and they came with one of the nose-pad struts badly bent. The box was also missing the correct label and bar-code and felt very cheap. I eventually took them to an authorized Ray Ban dealer, and they were very unsure if they were authentic, initially outright calling them fake. Although they never gave me a concrete yes or no answer, they refused to call them real.<br /><br />I am personally convinced that they are fake and I am returning them. I bought both pairs from Amazon itself, and I am very disappointed that Amazon would sell a fake item and claim that it is real. Although it is possible to get an authentic pair, just know that you are taking a gamble!