not quite as Ultra Flat ...

The Xperia M weighs about 115g with Battery and 9mm deep, the case about 55g and 18mm. The product "18g incl. Packaging" is simply wrong. Whether you can talk with a doubling of the depth and at least 50% more weight of "Ultra Slim" - I do not know ...
The bag is, as far as I can tell so far, well finished and touches his pleasant. The mobile phone is clamped in a hard shell and therefore very well protected. You get it relatively simple used to it again take out though (I use my Xperia as Sports Tracker and take it for a run bag with - that does not work with flip-case) is quite fiddly and it gives me the possibility already fallen down. A removal aid, for example in the form of a flap, would be desirable.