I have gotten a fake g shock watch before. And it does look like the legit one, even the metal backing also looks the same. So how to differentiate? 1. Press all 4 buttons on the side of the watch (all at once). Wait 2 seconds and if the light changes to another color means its a fake watch. If you keep doing this you will realise that the LED color will change from blue --> red --> green --> yellow/ orange --> may have some other light colors then lastly it has rainbow lights. 2. The price that it is being sold is too good to be true. Dont buy if the price is too good to be true. The seller might be scamming you. 3. It is good to do some research on the model that you are interested in e.g how many modes it has, features? 4. The seller should give you warranty for the watch and battery (i dont remember how long). I.e if your watch batteries die before the warranty period is up or there are problems with the watch then they will help you to change or fix. I got a warranty card when i purchased my watch.