Check the listing for details. 3000 Grit Whetstone Polishing Knife Sharpener Ruby Stone Sharpening 10cm Length. Color: Red, Condition: New. Listed at 13.79 USD. Item Specifics: 100% Brand new and high qualityMaterial: Ruby StoneColor: RedGrit: 3000#Length: 100mm 1 PC 6 Types 3000# Grit Ruby Whetstone Kitchen Knife Sharpener Sharpening Graver Stone Oil Stone The Ruby Sharpening stone is made from sintered crystals of synthetic ruby.It's extremely hard, maintain their shape well and are resistant to wear. Because they are so hard they can sharpen and finish extremely hard metals such as carbide gravers, but also work on non-metal like glass, porcelain and quartz.For sharpening and polishing chilled steel,alloy steel and precision parts etc.These Ruby Sharpening stones can sharpening and polishing for triangle sawtooth, circular saw blade, plane blade edge, small serrated mould.Sharpening stone can use oil or water. Grit: 3000 Type: 001 square Ruby Size: 100mm*8mm*8mm 002 triangle Ruby Size: 100mm*9mm*9mm*9mm 003 semicircle Ruby Size: 100mm*8mm 004 cylindrical Ruby Size: 100mm*8mm 005 edge Ruby Size: 100mm*5mm*9mm 006 rectangle Ruby Size: 100mm*10mm*5mm 1 Pc Ruby Sharpening Grindstone