There is nothing wrong with the model itself, but I don't like how it looks when it is in the printer. Flat versions are available that showcase the bottom layer of the cover instead, which I prefer.
(Sorry for the lousy picture quality, the black filament was a bit of a problem)
Print out quickly and in a very good quality. But I'm not sure if they are really useful .. they sit a little bit loose and ... do they actually have a protective function?