The Sterling sharpener is designed to shave a small amout of steel from the edge. This is only good for relatively soft steel. If the steel is to hard and brittle the edge can be ripped up. Shapeners with ceramic sticks are better for high quality knives. They are available with fixed sharpening angles so even people with little practice can achieve good results.
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If it isn´t broken, it doesn´t have enough features yet.