ULTRA-SHARP Diamond Sharpening Stones are the best value we've ever seen in a diamond sharpener. It is a quality stone and the first stone we grab for around here. 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"! Simply return the stone to us and we'll either replace it or give you a full refund whichever you prefer. No questions asked. 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!