Grindstone - TOOGOO (R) Grindstone Whetstone Water Grindstone Kitchen Knife 10.000 Gravel Material: Natural Jade Model: 10,000 grit Size: 50 x 20 x 10mm (1.97 x 0.79 x 0.39 inch) Net Weight: approx. 30g These professional grindstone are excellent for steel knives, cooking and kitchen, outdoor or hunting knife.