As a professional knife maker, I would like to suggest that you take a sidewalk chalk and try to sharpen your knives with it. This is an absolute waste of money. Worst "diamond stones" I have ever used. Couldn't even sharpen one knife from the whole set as they wore out during the first 5 or 6 passes at each grit. My bevels are clean and sharp since my good stones are about 3 years old and have sharpened hundreds of knives. I decided to give it a try and see if new stones would save me anytime. nope! Save yourself the frustration and just throw them in the trash before you even try to use them. Better yet, don't buy them in the first place. I would give them a zero star rating but I can't.