Wüsthof’s easy-to-use knife sharpener is an ideal addition to most households. Two stages of sharpening ensure even the more stubborn dull edges can be brought back to life. The coarse side of the sharpener is made of carbide to only be used on the dullest knives. The fine ceramic side can be used with more frequency to recondition a dull blade. NOTE: This is not a maintenance tool. Use only when necessary.