I purchased a pair sunglasses from F21 a few years back and I believe I got gifted with the original. So...with that said, you really don't need to spend a pretty penny on some priceys shades if you just look for the dupe to them!
As you can see so far the only difference is the tint in the lens. In person you can't detect the differences at all. The only thing you can detect from the lens is one is a smidge darker than the other.
Side by side the hues in the lens pop out more. Can you tell yet?lol
Okay if you said A. is the fake your right! B. is the real one.
If you tilt the shades to the side you should be able to detect the trademark name on either side of the upper portion of the lens as well as a serial number of some sort.
You can't go wrong with either! Both are gems!
F21: $5 or less