Prompt receipt. However, these earplugs are not really suited to my ears, and remain difficult in place: they end up not far out of the ears without actually filter out sounds. The noise is filtered but far from being mitigated. A book may be only a removal of large noise.
EDIT The Author: Finally, the problem is partially solved by returning earplugs (outside to inside). It's bigger so it holds better and that better filter. But hey, it is not intended to cause ...