The first thing to check is the overall quality of the product. Note errors in grammar and spelling, and check to see if something is printed. Also, check to paint and wear. Make sure the paint is intact and not chipped.
2. Nose Piece
Look for the "RB" emblem on the nose pads on models with adjustable nose pads (such as the Aviator). Counterfeits are likely to embed low-quality etchings. So, when evaluating the legitimacy of Ray-Band sunglasses, make sure you pay particular attention to the nose piece.
Raise your arms and make sure that the prints are centered. Many real ones can appear slightly off-center, but they should be close to the center.
Check out the Ray-Ban logo as well. Ray-Ban places one logo (a subtle 'RB') on the glasses' left lens and one on the right. The glasses can be fake if the logo looks blurry, out of place, or scratched off. As you tilt the lens toward the light, you should be able to see the etching in the lens very clearly as it's hard to notice usually. Counterfeit Ray-Ban glasses do the etching in poor quality, making it easier to see.
Another good way to tell is to run your finger along the edges of the frame and feel for seams. Ray-Ban hand-makes all its acetate frames from a single block, so there should be no seams along the temples or around the lenses. In addition, these details are extremely difficult to reproduce, and most counterfeiters prefer to avoid them.
However, some counterfeiters will attempt to reproduce it. If you have purchased a fake Ray-Ban pair, check the temple carefully. You shouldn't feel or see any glue or uneven edges.
Before buying eyeglasses, be aware that highly inexpensive glasses are often low quality. A pair of Ray-Band glasses can cost anywhere from about $150 to $500, depending on the model and the frame's weight. If the discounted price is significantly lower than the original cost, it could be possible the glasses are fake.
Inside each pair of glasses, the serial number will be on the left temple arm of a genuine Ray-Ban sunglasses. It begins with RB and appears clearly etched, centered, and aligned with the arm.
8. Warranty Card
Ray-Ban sunglasses come with Ray-Ban cases, often marked with the Ray-Ban logo. Look for the logo on the case; fake ones often do not have it. Look inside the instructions notebook for any spelling errors. Counterfeit usually gets this wrong. You should also see a grey Ray-Ban cleaning cloth inside a clear plastic wrapper.