exactly what I was looking for 11

Since the Ativ S has a very smooth back and is not due to its size, therefore, "optimal" in hand, I was looking for a protective sheath which applies little, fits perfectly and visually hardly noticeable.
Exactly these criteria are met the Mumbi Cases in my view to 100%.
The material is a little harder than some cheap "flea market covers" so that a sagging of the envelope, with frequent removal and replacement (eg. If you put the Ativ S in a charging cradle) is not possible.
Fit = Perfect! All holes are exactly where they should be. The headset, which beiligt the phone fits well with the protective cover still easily into the socket.
The shell is minimal at the front on the edges to protect the display when you placed the Ativ times with the front down on the table.
The only complaint: the use of a USB charger does not work with the shell. But unfortunately she wears on too thick.

Conclusion: strong buy recommendation for the product!