I came across a sharpener having a defect.

I bought originally to sharpen the teeth of the knife blades, which it does very well, who purchased two sharpeners / sharpeners that give me any satisfaction. However, I looked more closely this article and I'm guessing that the "finish" supposed to bring a final touch to a sharpening was a space of a few tenths of a millimeter between the two parts of ceramic, resulting that the cutting edge a knife blade was only in contact with the plastic of the sharpener. I found that there was a Phillips screw that can be enabled once loosened to advance a ceramic parts (although there is little game to do so) to make this part of effective sharpener. Although the Phillips screwdriver just adapting to the screw, I have not managed to loosen it (forced or bonded?). I gave up for not damaging the head. As this is the least aggressive of the sharpener, I imagine a person not attentive risk of damaging the edge of a good knife that ESTL no plans to cut hard plastic. I warned the Amazon problem, although not the seller of this article, proposed immediately to reimburse me. Hats off to the after sales service of Amazon, I put the challenge to find a brand of mail as efficient and understanding.