If you want to use the Apple Smart cover (instead of a bigger, heavier, "all encompassing" leather cover then this is what you need to protect the back of your precious iPad.
It is a good fit, slim enough to add very little depth to the iPad, light enough to add very little weight, robust enough to offer a reasonable degree of protection and, being clear, has virtually no impact on the visual elegance of the machine.
I really do not understand the negative comments made by others about the buttons. Yes, there is a layer of plastic over them, and it is raised to make it easier to locate them. Operating the buttons is as easy without the cover as it s with it.
As for the suggestion that there is no space for the charging cable, I can only assume the reviewer had put it on the wrong way round. Be assured that there are spaces for the charging/sync cable, the earphone socket, the camera, the lock switch, the mic and the speaker. The lower edge is cut back to allow the Smart cover to attach to the iPad.