Personally, we aren’t sure what the meaning of “U” letter on the Sony Xperia U means. The same thought also cross in our mind for the brother and sister of this newest smartphone by Sony: The Sony Xperia P and Xperia S. Could it be that U means for Ultimate or U for Ultra? I don’t know. But, what the point is that this phone also know as Sony Xperia ST25i / ST25 Kumquat. You may found also that this phone also uses ST25a code series. It just a given name for regional usage, usually due to the carrier of data networks frequency. ST25a for north America which uses HSDPA 850 / 1900 and 2100 Mhz but for ST25i it uses 900 / 2100 Mhz. That’s it
Comparing the Xperia P, Xperia U and Xperia S, this phone — the U version– supposed to be had a middle grade between the S and P. It powered with Dual core 1GHz STE U8500 chipset with DB8500 GPU and 512 MB RAM. Unfortunately the internal storage is just available for 4GB. For many users, nowadays, this kind of size of internal storage built-in memory arent “space” enough. More importantly, the fact that the Xperia U didn’t support for external microSD card slot. Storing huge video and photos would be a little bit problem on this phone.
Btw, the bottom cover is exchangeable. As you can see it can be replace with yellow, white, pink, or black. But the body only available for black and white (back cover).