I ordered the envelope because I was looking for a full Silicone Case (ie completely soft). The title of the product seemed to promise it and I ordered because of the low price it. Today it has arrived. The fit is perfect, the side edges are made of silicone, but the back is a hard shell. Otherwise would have little details like sound up / down buttons and the standby button can be worked out. These have fallen very flat, still function normally.
Altogether, 4/5 star because of the small details, but also because I was misled by the description a little.