TAIDEA Diamond Knife Sharpeners are continuous diamond surface sharpening stones. TAIDEA uses 360 grit and 600 grit Monocrystalline diamonds that are securely bonded in nickel, and then electroplated onto a solid stainless steel plate. The uninterrupted diamond sharpening surface makes a Diamond knife sharpener an ideal tool for putting a razor edge on knives, as well as pointed tools, and tools with a small contact area. Unlike a conventional knife sharpener, a TAIDEA Diamond Knife Sharpener stays perfectly flat for precise sharpening, won't develop grooves or hollows, and never needs dressing. They work perfectly well dry, but water may be used as a lubricant. Oil is not recommended.