The genuine one on the left has a straight nozzle, while the fake on the right is somewhat bumpy.
If you take them apart, the catch under the nozzle has a larger diameter on the genuine one.
So the fake tends to leak in the wrong places more often.
Also, when you squeeze the bottle with the nozzle closed, the genuine one doesn't let water out, but the fake can't withstand the pressure and the nozzle gets pushed up, letting water out.
The bottom design of the bottle is different, and the lettering is different too.
Decisively, the genuine one has a completely soft body so it's easy to squeeze water out.
The weight is almost the same at around 50 grams, so aside from the fake being a bit cheaper, there's no merit.
I didn't want to know this stuff either...T.T
