This ULTRA-SHARP Diamond Sharpening Stone Set is the best value we've ever seen in a diamond sharpener. We've tested every diamond sharpening stone made and the Ultra Sharp perform better than any of them. The stones are made of micronized monocrystalline diamonds that are electroplated to the surface of metal plates which provides outstanding durability. This set includes three diamond sharpening stones plus the universal stone holder to keep the stones firmly in place while you are sharpening. These extremely fast honing 300, 600 and 1200 grit diamond stones will quickly sharpen anything with a cutting edge including high carbon, stainless, and ceramic knives! We're so confident in these stones that we back them with our "No Questions Asked 100% Satisfaction Guarantee"! Whether you are a chef, sportsman, woodworker or knife enthusiast, Ultra Sharp diamond sharpening stones will quickly give you the results you need. You won't be disappointed!