USB3 case

I first thought I did not have a case because the USB3 socket is not at all trditionnel format my drive 2.5 inch USB3.
It must be said that taking that goes into the hard drive is kind of mini USB2.
So I grew to be deceived and asked Amazon to take back what they have accepted without question even sending me the file with the labels to stick on the return package (BRAVO).
After testing, I found that the device is the USB3 and I kept. Since then, I have a friend who also purchased a similar case and there it has a cable with two plugs USB2 normal format.
The disadvantage is that it must not forget its cable when you go through something because it is more than likely that nobody will have such a specific cable for me and for him. Keep iniformisation the cables and, for now, I know at least three different connectors and mutually incompatible? It's a pity