The shell serves its purpose, but it is in the closed state only loosely on the display and therefore can be opened easily or slip. So you should not expect too much protection happens when you lose the touch with sharp objects in a pocket (what but anyway not a good idea). On the other hand, it is sometimes a bit fiddly to open the envelope, if the note is a front because it is flush with the edge of the note, and to get them to take not always good. The grade is relatively difficult along with the shell. This is to keep a hand in the long term a bit uncomfortable. The first envelope I had to send back because she began after a while to break down at a corner and on. I hope the second is better processed.
Update June 2015: Here it is now in the second envelope at the same corner (bottom right) gradually ripped the plastic, without the shell would ever particularly strained or even fell down. Therefore, now only two points.
