The protective cover is relatively thin, the "spine" acts not very robust and the rear corresponds exactly to the original battery cover.
[If you want to set these original envelope, which can choose the actual cell phone for the price. The differences in color (black, white, green, orange) relate namely only the back - and is completely replaced by the "Book Cover"
(Note !!! 1. Please comment. My statement is not correct, unfortunately. There are two frame variants. A silver and black. !!!)]
Once one has plugged his phone into the cover, then the first impression repaired immediately. It fits, all functions are freely accessible and as fragile as the first impression suggests let out of the box, then the cover is fortunately not yet.
The advantage of the cover is very clear that it makes the phone neither thick nor heavy. And because the back of the original rear corresponds to work even wireless charging - provided you the appropriate station buys it.
The disadvantage is that the side of the phone is not protected. The aluminum frame is likely that little account, but a softer plastic or leather on the side would be a fall safely absorb anything and thus also protect the inner workings of the cell phone a little better.
I am but overall very happy with the book cover, even though it has a high price. Although the is likely to be partly due to the items in the back that enable wireless charging, but probably few will use because you have to buy the charger.