Authentic Ray Bans are supposed to feel a bit heavy and are constructed in such a way that, the ‘’struts’’ that sit on your ears are metallic, thus making them a bit heavy. If the ones you are thinking of buying feel too light or fragile, then they're fake.
The lenses of real Ray Bans are made of pure metallic glass. So to avoid buying the wrong thing, give the lens a gentle flick and watch out for the sound. Real glass should make a ‘’clinking’’ sound otherwise, it isn’t authentic.
Low quality metal-hinges
Inspect the hinges of the Ray Bans; they are supposed to have top quality metal construction. If it appears otherwise, then it’s not the real thing.
Nose pad quality
Every authentic pair of Ray Bans should have a firm and comfortable nose pad. If the nose pad of those Ray Bans are hurting you or are not comfortable in any way at all, it’s probably because they aren't the genuine article.
Take a look at the Ray Bans from the side and see if there’s any cursive ‘’Ray Ban’’ logo attached to it. Make sure you take a good look at it. It should be professionally attached without any flaws. If the logo on your Ray Bans are not cleanly attached, then it isn’t the real thing.
Model number inside arms of glasses
Check your Ray Ban for a serial numbers. It is usually located on the inside of the arms. Make sure they match with the serial number on the box that comes with it. If you don’t find any serial numbers or they don't match, then don't bother buying them.
Beware of special offers that often pretend like they are selling the real thing for reasonable prices. Be smart enough to realize that it’s probably because they are fake.