Following the recommendation of a friend, I then decided to use these double sharpener.
And I'm really surprised! There is a rough side to prepare the cutting really blunt blades again and the fine ceramic side, to pull off the edge.
It works perfectly and I can put my outdoor knives sharpen whenever necessary. Of course, I've already dug about our kitchen knife - with super result!
On the top and bottom there are small rubber label, so that you can stop the knife sharpener on a smooth surface without him slipping.
I merely exchanged the thin chain against paracord.
Strong buy recommendation.