This equipment DOES sharpen CERAMIC ZIRCONIUM OXIDE knives and is ESSENTIAL to anybody who is fanatical about obtaining the SHARPEST edge. It is unbelievable. It has put a razor edge on my Kyocera Chef's knife that is sharper than a Stanley Craft Knife blade in 30 seconds flat. Now it slides effortlessly through everything like a hot knife through butter .. including cardboard when it comes to opening boxes. The Stanley is redundant. Needless to say it slices through vegetables like nobody's business, even those irritating stringy spring onions. Wheesh Edit: We wouldn't reccommend using these kives to open boxes - its simply too good for that!