How to tell the difference between an iphone4 and a fake?

My friend bought an iphone 4, the other day. Then i heard rumours that there were fake iphones. So i let him know and now he wants to know if he's is a fake or real… How can i tell?

There's several different ways you can tell.

Visually most I've come across don't have apples trademark logo or the "made in California" info on the rear. Some of them don't have the square shape icon on the circle below the screen; so it's a bit more like the 5S in this regard. Some of them aren't even the same dimensions as the real thing, but you couldn't tell unless you put a known fake and known genuine side by side.

iTunes will only pickup genuine original products, not fakes and also only using cables that are apple certified.

You can go to Settings then General then about. Find the serial number here and enter it in here
https://selfsolve.apple.com/...Dynamic.do

It's easy, the price, weight, battery and others, i think it is to distinguish them…

I think you can also check the serial number on the apple website.