SODIAL(R) Combination Grit Double Sided Knife Honing Sharpener Sharpening Stone Whetstone Two kind of sharpening Stone: Orange corundum Whetstone, also known as orange stone, abrasive cutting edges sharp, good finish, high durability, hardness and corundum similar, good toughness, usually better than corundum grinding performance for tool steel, alloy steel, hardened steel molding grinding, especially for a variety of cutting tools, measuring tools, instrument parts for finish grinding of workpieces requiring high Gray carbon Whetstone, with high hardness and a certain toughness, hardness second only to boron Whetstone, abrasive sharp, good thermal conductivity, used for optical glass, tungsten carbide, titanium, agate, cylinder liner, bearing steel polishing, sharpening high-speed steel cutting tools, but also for energy originals, ceramics and polishing hard and brittle materials such as boron carbide Whetstone, is a high hardness abrasive, grinding capacity Specification: 100% Brand new and high quality.