i have tried on Xperia U and i saw is normal sim tray and i never check the package inside the box as if im not wrong, it will come with a microsim adapter included.

I will go get the Xperia U today and will update u all...maybe i will put a photos wat is inlcuded in the package

Just a to add one more thing, the storage for Xperia U is 4GB usable only.