The blue shell is like the included black cover, a Nokia original, and therefore fits perfectly around the phone. It looks like the actual shell, had indeed should be. The Lumia 800 is thus only slightly larger, but again additionally protected. The openings, whether for speaker, buttons or ports fit wonderfully. There is no unnecessary gaps. To the neutral black phone the blue sleeve fits beautifully. Especially when you as a live tile color the matching blue set. You have enough of the supplied case, is the shell, no matter what color, definitely the right choice.
Who ordered the shell, has been a Lumia 800 or wants to establish one where a shell in the corresponding color is already such case. Therefore, we know how good or bad is the shell. This here is the same. Only in blue; o)
Incidentally, the Lumia 800 fits so well into the dashboard mounting bracket for the N9.